I don't know who Thomas is, but have you tried to reach Matt Peak? Bottleneck has done a few projects with him (some referencing his father) so that might be a good way to start.
I'm pretty sure this poster was never printed. I worked at multiple studios, and multiple agencies/designers are hired on any given project. Lots, LOTS of leftovers, which some people like to collect. Discarded designs (obviously not good enough) is a weird thing to collect, but whatever. If you like a specific artist, it makes more sense.
My 2c.
T