There are some low-priced Lexicon processors out there like the MPX-110 and MPX-200. They have better quality effects than any multiFX-pedal, and maybe even single effect boxes. And they don't have a pre-amp, which you shouldn't need with that amp of yours'.
Also, you might want to check out the Behringer Virtualizer. Which is even more flexible than the Lexicon stuff, and probably cheaper too.
