Looks like the Folklore Hunt might be worth some effort - there are some really nice prizes out there, for only 1L each. Many of them are perfect for fantasy RP.
I've just dipped my toes in it so far - and picked up a couple of nice gowns, and a chalwar/bellydance outfit.
Siryelle Yalin may be best known for her amazing furniture range, Tempura Decors, but her fashion line Siryelle's Dreams is going from strength to strength.
Although she's not strictly speaking a silks designer, she has made some outfits that dancing girls would feel perfectly at home in.
One of these is the glamorous Silky Laetitia outfit.