It sounds like you have done your homework. I agree with Darin, a warmed up 22RE will be the easiest and most ecomonical option and you won't have to worry about the rest of the drivetrain being taxed by the additional power and weight that some of the other swaps offer.

If you have access to a cheap 2.4L from a Taco though then I think that would make a good swap, and if it is still not enough power for you, just add a TRD supercharger. <img src="/forums/images/graemlins/evil.gif" alt="" />