I need a small tree (25'). One priority is that it be relatively fast growing because it's a privacy issue -- our neighbor's backyard is elevated above ours and I want something to give us some privacy from their patio, which looks down onto ours. And I want a small tree, not a large shrub (I want the openness at the bottom). A multi-trunked tree would work.

Ideally, this fast-growing tree will have multi-season interest. I'd put great fall color (just not yellow) at the top, followed by interesting bark/branch structure/other winter interest, with flowering at the bottom of the list (not that it's not of interest, but fall/winter things are of more interest).

No serious fruit litter problems either, since it's going to be near/over one end of the patio.

I'd really appreciate your input. Are any of the Acer palmatums fast growing? Any other ideas? I've been toying with Cornus mas but it appears that the fall color isn't that great (?) and it isn't that fast-growing (?). Help! and thanks! :)