Thanks for the responses, guys. I'm a little surprised that there isn't an Indiana Jones voice pack. I imagine someone more enterprising than myself could cobble one together out of Indiana Jones and the Fate of Atlantis, but I can't even find the sound files there.
Hmm, good suggestion Or, but I think that's a bit too noble for Conan.
I've been toying with this today, and here's what I'm thinking:
Mandrake = cq_drstrange
Spider = cq_moon_knight
Miss Fury = cq_elektra?
Avenger = male_menacing
Green Lama = maledruid
Kato = MaleMonk
John Sunlight = sh_Magneto
Doc Savage = sh_superman
Obviously, I'd need generic versions of some of those, but that's easy enough to do.