dpurq, that reminds me of the Skiffle craze that sprang up around Lonnie Donegan back in 1956, the amateur Skiffle groups (and some of the pros) used what they called a tea chest bass, similar principle to your instrument but much cheaper.
It consisted of a tea chest, or similar sized lightweight box, and a broom handle; played with one foot on one corner of the box and the broomstick in the opposite corner. Tuning did tend to be somewhat hit and miss. The thing played havoc with the fingers, but the amount of alcohol consumed usually deadened any pain ........ until the morning. The rest of the group played guitar, banjo or such other similar instruments they could lay their hands on.