Okay, I've compiled a list of class suggestions that I thought would interest me, including a few mentioned before. I apologize for its length, but hopefully I might spark other people's imaginations, as well. Maybe I've even thought of a few you haven't. I've elaborated where I thought it necessary.
Masbate Nomad--as mentioned before, a character like Samu. Probably a cross between a Barbarian and a Ranger.
Lastlands Mercenary--a less principled fighter, probably with a variety of sneaky moves.
Giak Foot Soldier--because who doesn't want to play a Giak?
Gourgaz Captain--the only thing better than playing a Giak....
Starn Sentinel--for those who want to play a giant.
Knight of the White Mountain
Bhanarian Brawler--I'm thinking something along the lines of a monk here.
Vassagonian Sky Cavalryman--yeah, Itikar!
Tyso Outriders--I made these guys up on Tower of the Sun, but they're essentially mounted rangers that function as agent retrievers and light cavalry.
Pit Fighter--reflecting all the times there are gladiatorial matches in Lone Wolf.
Xanon Stalker--those creepy crocodilians, represented as a class. I'm pretty sure this is what they're called.
Agarashi Cutthroat--why would I want to leave out the Agarashi when I could suggest a class for them?
Guild Thief of Tahou--one of the cooler side-plots in Lone Wolf includes these guys, so why not make them the standard thief class? The game needs one.
Kadan Assassin--one of the cooler guilds from Lone Wolf, in the Skull of Agarash.
Noodnic Cutpurse--yeah, Noodnics!
Ice Barbarian Scout
Asajir Troubador--because every game needs a bard, no matter how lame that class is.
Ghagrim Tracker--because I love Ghagrim, and think they'd be cool to play.
Disgruntled Dwarven Bartender--I think we all remember this one-eyed fellow.
Kakarmi Scout--why not include one of the other intelligent races?
Vazhag Skulker--creepy rat men are cool.
Kloon Scholar--can't forget the Kloons.
Drakkar Ziran--seems like a good option for evil combat mages.
Giak Shaman--another option for same.
Redeemer--probably functions like a straight-up Cleric, with LW desperately needs.
Acolyte of Vashna--and why aren't these guys available? This'd be like an evil Cleric, I'd think.
Dazudskul Necromancer--Kezoor and his ilk, put into a class.
Liganim--another evil mage class.
Nadziran--the foremost evil mage class.