There are like a million answers to your questions! :)

About the peaches, i doubt you want dwarfing rootstock in your zone. Zone 5 is iffy for peaches to begin with, so i'd stick to a normal rootstock. The key would be pruning. Prune prune prune if you want a smaller tree. Thats my plan here @ home, because i've got a small area, with lots of different trees.

Apples can come on all different types of rootstock. I think maybe Bud 9 would work or EMLA 9 or 26? I'm thinking Granny Smith isn't good for this climate, but i may be wrong. There are excellent other choices.

Search gardenweb/google/grab a book @ the library. I'm constantly learning new things.

Maybe check with Miller Nurseries. They have what they call a compspur apple that only gets about 8 ft. My daughter likes granny smith as well, so I got one of those and a red rome compspur from them this year. Very good size bare root stock. I was happy with what I got, but don't know anything about growing apples. Maybe someone else can chime in about the compspur.

I'm sold on small fruit trees. Although - what is best for your zone and mine are two different things - as regards to selection.

If I had it to do over again, I would have all dwarf trees. So far I have 6 or 7 along with about 4 standards. The small trees produce very well - and for our small family of 3, we have more than enough from them. I also need to cull a lot, because they produce way too much for their small size in the beginning.

Most of my trees were purchased locally, during bare root season, and are quite easy to find. Most of them are only 4 feet tall and about 3 feet wide, with their central leader removed, so they grow shorter.

You should be able to find many apple types - especially if you have chill hours. That is a problem with my zone - and that is why selection is important. But with the proper choices, they can be very productive.

You might try a catalog company named Raintree Nursery - although again, not sure if they ship to your state or not. They have many dwarf fruit trees, on special root stock, although your local nursery should be able to supply you as well.

Dwarf trees are fun -

Bejay

Have you looked at genetic dwarf peach trees? They have a much denser leaf node spacing so they have a lot of foliage and have a heavy crop of first class peaches. I don't know how well they are suited for your climate. They were developed in California from what I understand (cross bred with a miniature Asian variety?).

One of the more prolific breeders of miniature peaches and nectarines is Floyd Zaiger. Here is a link to a list of many of his introductions. Scroll down to miniature nectarines and then to miniature peaches.

Here is a link that might be useful: Floyd Zaiger

If you have a sturdy fence you could try espaliers, fans or cordons which wouldn't shade your borders at all, providing your neighbour allowed access to the back of the fence for training and pruning.