Where do you live? Need to know region, soil conditions etc.

We're in Seattle.

What other requirements, like leaf or flower characteristics, particular manner of growth?

Yes, it's kind of a broad topic without any more qualifiers than just size and light requirements. I'd be inclined to visit some local nurseries to see what you might like. Not the best time of year for an ideal selection, especially for deciduous shrubs, but you would certainly get a representation of broadleaf evergreens or dwarf conifers. Wells Medina or Swanson's should have a decent selection of both.

For a decidious shrub with multiple seasons of interest, dwarf fothergilla would be on my short list.

I love winterberry. You have to have a male and female to get fruiting.

'Yuletide' camellia is something you can find in season now and might appeal.

Victoria (California Lilac) is a real looker, especially in summer when it flowers. Has a very clean look the rest of the year, green and shiny. Grows as big as you specified and loves sun...perfect!

Not a few ceanothus shrubs in this area may develop a detracting leafhopper buildup during summer, their leaves becoming conspicuously yellow-blotched as a result of the insects' attentions. I don't remember how 'Victoria' specifically fares in this respect.

Dense and compact, 'Skylark'* has a dome-shaped form to 4 feet tall and 6 feet wide, making it a good choice for smaller gardens... 'Skylark' has demonstrated a wide tolerance of climate and soil types... In 1972, plants survived repeated nights of 10 F(-12 C) with daytime temperatures not rising above 30 F(-1 C)

--Fross/Wilken, Ceanothus (2006, Timber Press, Portland)

*Thought to be the same as 'Victoria'

If 'Victoria' and 'Skylark' are indeed the same plant (which I doubt), then you need to adjust that size significantly. 'Victoria' will rapidly get to about double that size, making it somewhat less suitable for smaller gardens.

And IME, 'Victoria' is not overly affected by leafhoppers. But then I've yet to see this a significant problem here with any ceanothus provided they are given optimum growing conditons and not coddled by way of rich soils, fertilization or excessive irrigation.

I bought one of each so-labeled and planted them near one another last spring. So far they are interchangeable, but they have not developed much and I don't know how they were identified by the growers. If the one producing the 'Skylark' had acquired the same clone being sold by others as 'Victoria' and put it out as 'Skylark' because

It is believed by many to be the same plant grown in the nursery trade as C. thyrsiflorus 'Victoria' (same reference)

then I've just got two pieces of one plant with two names.

I haven't noticed any connection between environment and infestation, except maybe the worst cases being in more hot and dry spots - like with other sucking pests such as mites. Not all California lilacs are from hot and dry areas, many are limited to cool outer coastal sites in nature. Fross/Wilken repeatedly mention if a given kind can be cultivated on the coast and if it can be grown in hot inland (California) valleys. And you'd expect horticultural selections being found to be able to grow under nursery irrigation regimes as well as in gardens in cool climates - the ones we see in outlets here - would also not necessarily be as successful in hot and dry conditions as others.

There are a number of hardy fuchias you might find acceptable.

Fothergillia gardenii (dwarf fothergillia) is a great shrub for me. Although it is supposed to get 2-3 feet tall mine is about 4 feet after 4-5 years. It has nice summer foliage, sweet smelling spring flowers and outstanding fall color. It also looks decent in the winter as the branches have a zigzag pattern. Sunset says it needs moist soil but mine is growing in an area that gets little summer water and is doing great.

I find fothergillas to be quite prone to drought. The best one is Fothergilla major but it is seldom seen in nurseries these days.

The best one is Fothergilla major

The "best" one?......what does that mean, exactly?? The best in your opinion? Better flowering? Better fall coloring? More disease resistance (not that this is a significant criteria for fothergilla)? It just seems like a very subjective statement with little to support it. And it tends to get made too frequently. If ultimate size is a consideration, F. gardenii or any of its cultivars may indeed be a better choice with little, if any, difference in any other attributes.

btw, I've seen both F. major 'Mt. Airy' and 'Blue Shadow' at several area nurseries this season so cultivars ARE available, if not the straight species.

Larger leaves, thicker stems and taller stature make it more impressive - more like a Hamamelis. 'Mt. Airy' is considered a hybrid and has a similar general appearance to F. gardenii. 'Blue Shadow' is from Gary Handy, it seems that the picture that was on the Handy nursery web site made it look similar to 'Blue Mist'. If this is the same new blue one that has been in local outlets these plants have also looked to me to have the thinner, weaker stems and smaller leaves of F. gardenii. Maybe it is a hybrid also.