Funny thing, I was going to do a flute quartet this year, too. But the schedule/rehearsals didn't fit. So I dropped it. But then another girl did as well. Poor advanced level quartet is now a duet...anyways. :P sry. Off topic.

How about...Jour D'ete a la Montagne by Eugene Bozza? Pretty impressive piece but really difficult & ambitious choice. If you have 4 really talented members (as "advanced" can vary for diff high schools) in your group, then it'll work. If not, then don't. There's another one I've heard that I think could work for an advanced high school flute quartet, Rondo Capriccioso by Robert Russell Bennett,

There is a kinda cool and kinda weird one called 'one for four' I think.