OK, I decided to switch gears here. I got the Whammy, and while the board is the same (older model

), there is a lot of components missing from the Whammy. By a stroke of good fortune, I just picked up a Modulator, which apart from 3 DRAM's, and the PROM, is only missing the MC34064, some caps, and a resistor. One thing that struck me was that there is no PROM, and only one DRAM in the Whammy. I'm wondering if I remove the PROM from the Modulator, if it becomes a Whammy

. I'm going to try that. If it's the case, then I'll piggyback everything into the Modulator, and use a rotary switch to switch between pedals.
I did find a web page which describes quite well how to piggyback PROM's for dual booting. It's not specific to these PROM's, but should apply to them as well.
http://www.nerd-out.com/darrenk/500W/DualBoot_piggyback.htmSlowly but surely....