@What4 just posted one for sale on another thread if you haven't found one yet... which I suspect, since they are hard to find.
https://expeditionportal.com/forum/threads/6-5-ft-flippac.228793/
Looks like a pretty good value, that size is hard to find. Any chance you could post a pic on how you did the panel mount? I've been thinking of trying something similar on my Flippac.