nashidesei: Lu (a less mad scientist one, though)
xerne: Hojo (always)
zoe_sama: Gast (ditto)
dabohaze: Shera (in-game, the more mousy variety)
turk_elena: Professor Rayleigh (she's a cameo in BC XD)
yukie1013: Fuhito (I don't know why. She fits many people, too. XD)

I probably forgot someone, but those are the ones off the top of my head.

~Cendri