Here some thoughts Fred.
One aspect of Permaculture is allowing the land to go with the natural flow of succesion. You would need to do a bit of leg work to find what natural plant comunities exist in your area. From there you start building your guilds which are nothing more than a term that discribes man-made plant comunities rather than those that occur naturally.
I mention all of this to remind you that veggetables are at the leading edge of the succesion curve. You can, and I do, think of vegetables in two ways. First I plug in as many perennial veggies as I can in the open areas that occur between tree based guilds plantings. This for me includes Jer. artichocks (edible tuber). These are tall sunflower like plants. I plant smaller annual veggies in front of them. The key here is perennial veggies.
The other way I tend the vegetable is in the old fashioned square foot raised beds. From here it not a matter of permaculture but rather using principles of companion planting. There are good books on this and of course the net.
Oh and a thought on blue berries. They like acid soil so plant them in relation with acid mulch producers like pines. Oaks leaves are also very acidic and are slow in decomposing.
So when creating guilds you can think of the pine as; acidic mulch producer, roots break up soil and brings up nutients and water, creates a moist mirco-climate under canopy, produces shade, a timber source, pine heart very flamable so is great for starting fires, forage and shelter for wildlife and I'm sure I could go on. And with all that I listed remember these are all very surface aspects of what the pine brings to the guild. The one aspect that no one seems to have done the research on yet are the unseen links between the plants in a guild and that is truely what we are experimenting with in guild creation. Heck many of the professionals will argue whether a living plant will actually share its store of nutrients with other plants. I've had it argued that wax myrtle, a Nitrogen fixing bush, does not improve the soils supply of avaliable N until the bushes death when its roots will decay and release the stored Nitrogen. In permaculture it is believd that plants share nutrients with those other plants in very close relationship with it through soil microbes transfer or simply secretion of the plant in question.
Watch your plants and learn from them. Look at what is naturally happening around you and try to think of how those relationships can work for you. Remember succession and go with tree based guilds if you have the room. That really is the goal of permaculture as see it. That along with the many other aspects of being and living with your fellow humans and nature;o)
Mike

Re: tomatoes, peppers & clover.

These should work well together. The clover shouldn't compete, as it is a legume, a nitrogen-FIXER (it draws nitrogen from the air and turns it into nodules of nitrogen on its roots), and the tomatoes & peppers are nitrogen-USERS. In your part of the country, lack of heat shouldn't be an issue in the growing season, so the clover would also help suppress weeds, cool the soil, and help retain moisture. If your soil is strongly alkaline, you may have trouble growing clover well.

Do you know what your soil pH is? Blueberries like quite acid soil, 5.0 to 5.8. If your soil is excessively alkaline (and, if it is, your water probably is, too), you may not be able to grow blueberries.

If you haven't had a soil test done, it might be a good idea to do so, so you will know where you stand. Most tests offer info on how to adjust your soil pH. Contact your local Cooperative Extension Service and ask them about soil tests, and if they think blueberries could be grown in the area.

Peaceful Valley Farm Supply in CA has good cover crop info in its paper catalog.

Sue

Here is a link that might be useful: Peaceful Valley Farm Supply

Other aspects of guild planting include the spatial aspect, both above and below ground, and water needs. Plant crops with similar water requirements together. Plant shallow rooted among deep rooted plants. Tall shade givers above those that like the protection. Tall sparsely leaved plants above those that like to see the sun. If it climbs, send it upward. The mind boggles!

Don't know about you, but I've put it the "too hard" basket for now!

Fred,
Establish your perennial Vegtables and herbs in seperate garden plots. You might already be doing this, but in the long run it will save you work. This way you can have an high fertility bed for market vegtables and lower fertility perennial garden bed for your herbs. It will save you work and is easier to look after as well.
One of the points of guilds is that they will look after themselves and not require a lot of work. So guilding perennial plants works well in this case.
Guilding vegtables can be mucho work with out noticable increases in crop yeilds. Here go with the bigeasyjock and use companion planting in order to maintain plant health and have benificial relationships between your plants. The age old example is planting basil in with tomato transplants. Tonnes on companion planting on net.
When trying to guild peppers remember that you are a market gardener. It would be wise to plant a compianion plant that will create a "sellable" product like lettuce. But this is where it gets interesting because peppers like it hot, hot, hot. In zone five, one of the best things to increase yields is to use a stone mulch around your peppers, no guilds. This way moisture is kept in the soil and heat is radiated to the plants at night.
OK.....slugs. Do you have a lot of mulch around your garden or places for slugs to breed and hide in? If yes, try to minimize these area'a while keeping your biodiversity. Slug traps are always a option. You can make your own out of diotamacious(sp) earth or left over beer in a beer can. more info available online, just look up slug traps. Removing mulch from around young plants also will lessen your slug damage as slugs love to breed in deep straw mulch and then eat the young plants.
General info on plant guilds is to think about how much space the plant needs to grow, how big and deep its roots are, how tall will it grow and does the plant have special attributes like nitrogen fixing or being a dynamic acumulator. Then you can plant plants together that will not compete for space above ground or below ground and help each other out. Instead they will grow together and shade out weeds and keep the soil moist. Oh and when trying to creat guilds for market gardens....try to think in terms of rows. So that you have a row of your tallest stuff at the back of your plot that will not shade out other plants, then a row of your next tallest in front of that and etc. Then you can put lettuce and basil around our tomatoes and some calendula pretty much where ever you want. This will help keep you in business with a product to sell. In my market garden i plant rows of companion plants next to each other. It is working so far!
Good Luck this spring,
BW

Hey Fred
There are dozens of combinations for plant companions, check the link for some books on the subject.
With the size of your yard you might want to check out, "Square Foot Gardening" by Mel Bartholomew , you can grow a lot in a little space
All the Best, Ron

Here is a link that might be useful: Companion Gardening