Soloing any class through SoA is easy enough, as SoA was never really designed to handle high-level characters. It is a whole different ballgame in ToB though, where I swear even the cats have +3 enchanted claws. [img]tongue.gif[/img]
Whereas you out-level everybody in SoA, everybody out-levels you in ToB. Very different situation. You are Elminister in SoA, and Rincewind in ToB( comments about the brutality of Mages in ToB will be ignored.
Bear with me for a while, I am trying to make an analogy here).
That said and done, I did further, further comtemplation and came to the conclusion that none of the Wizard-types are particularly hard to solo. For every roadblock I thought of, I eventually realised that there was a detour around it.
Ergo, I must eat more words and put forth my next suggestion. A pureclassed, non-kit Cleric. This is seriously one kit I have never heard of anybody even
attempting to solo ToB with.