how big is your choir and what kind of stuff do you typically do?
Im in a very small (picky picky we are) girls choir that typically does renaissance stuff, but we did this one fabulous 4 part harmony (it was murder at first, let me tell you) Called "Punching THe Dough" and its arranged by alice Parker.
its really fun to do and generally a very good piece.
oh wait, d'oh you said preferably accapella didnt you? XD link
(Rond Du Crepescule... Beautiful fairy like piece and sounds all twinkly and nice XD...be warned though, its in french! AUGH!)
we do most of our pieces acapella but these are a few in which we sang with a piano...erm Ill get back to you XD