Yes hard to find and most likely used
unisolar quit makeing STD framed panels several yrs ago
now they have stopped making panels suitable for RV use
they are now concentrating on large thin film panels for commercial grid tie and shingle style panels for commercial or residential use (apparently also for grid tie)
I'm happy to find these stick down 64w , 12v "nominal " system panels New at a good price
it is just over $2 watt, but they will integrate with what I already have, so I don't have to start over from scratch to have a larger system