If you like, I can do a voice set. I don't have any custom sounds, but if you tell me a character from XML2 or MUA that you think he'd sound like, I can put a set together. You can use NPCs, but they'll have less sounds to go with.
What I usually do is pick a voice set that makes sense from one of the games, but from a character I wouldn't normally play alongside Northstar. That way, he at least sounds unique when you're playing him. Maybe XML2 Iceman, with some "freeze" references omitted?