Interesting. I do have a few spare pickups around. And I have an LM386 headphone amp that I built a few years ago that could maybe drive a speaker or the headphone input on my amp, at least for experimenting. And I found some piezo transducers for under $10 on eBay, so experiments seem likely.
Given my lack of a bass amp, I have a new idea. Make the wooden box large enough to house a small 386-based amp (like a noisy cricket or something modded for bass) and a speaker. A self-contained stomp box sub-woofer thingy.