LordSephiroth-
Yes, there are a couple, kind of. There is Tashia, which will add a female sorceress, Kelsey, which I believe adds a male one...also present are Solaufien (who's quite good, maybe a bit overpowered), and Valen (who gets very overpowered at the end).
All are available at
http://www.cs.berkeley.edu/~weimer/bgate/