Jennie - How dense is the shade? Is it dappled like under trees, or is it heavy (no light whatsoever). If it is too heavy, you may not have luck with much. If it's dappled, you may want to consider some dogwood species. I know there are some shorter than Cornus florida, but you may have to search for them. I think there are also some shade vines you could train into standards if you're so inclined. Let me know about the shade and about how tall of a plant (mature height) you're looking for. I'll do some more digging and see what I come up with....

I've also included a link to an extensive online plant encyclopedia that I've found to be indespensible. The featured content is geared more toward Floridians (where I moved from) but many of the encyclopedia entries are invaluable to people in most zones.

Hope this helps!
--Joe

Here is a link that might be useful: Floridata