Bridesmaids need not dress alike: we all know this. But consider this, (you better sit), I don't think they need to be wearing dresses made by the same designer either! Oh my. I love the short champagne-y options for a crisp fall evening affair, and the shimmery greys would be lovely at any time.
If you ask me, the easiest way to go about the whole bridesmaid thing, would be to tell your friends what color you'd like them to wear and send them on their way. They'll be sure to get something flattering, something they can wear again, something in their own price range, and being your friends (with no doubt fantastic taste) they'll look fantastic! No worries. Best of all, NO dress fittings!
Lets see if I can remember where I found all these:

Halter Dress, from Betsey Johnson at eDressMe
Gold Party Dress by BCBG at eDressMe
ABS by Allen Schwartz Shantung Dress
BCBG Tulle Party Dress by Max Azaria at Nordstrom's
Tadashi Ruched Silk Dress at Nordstrom's
Strapless Tulle Party dress from BCDG at eDressMe