Warrior,
I too have an old Peavey midibass. The Spectrum bass module really sucks. I have one of those, too. I ended up using an Alesis Quadrasynth Plus module as the sound source. It works great, you can create your own sounds from the onboard voices and effects, plus you can import external files. The onboard sound library is fairly extensive and has lots of great usable voices, some them are huge. You should be able to pick one up fairly cheap these days.
As for patch switching, I tried a big fancy foot board with assignable pedals and such, but wound using a simple MidiMouse in the end. Three buttons: up, down and search. Very simple.
I too have an old Peavey midibass. The Spectrum bass module really sucks. I have one of those, too. I ended up using an Alesis Quadrasynth Plus module as the sound source. It works great, you can create your own sounds from the onboard voices and effects, plus you can import external files. The onboard sound library is fairly extensive and has lots of great usable voices, some them are huge. You should be able to pick one up fairly cheap these days.
As for patch switching, I tried a big fancy foot board with assignable pedals and such, but wound using a simple MidiMouse in the end. Three buttons: up, down and search. Very simple.