In the process of purging the hoarders nest that was the tiny basement frame shop I'd inherited, I came across a pile of old unmarked mailing tubes. They were mostly empty, and I set aside the ones that were large and long enough to use for incoming artwork. A couple were home to random pieces of art left unframed and unclaimed. This one was the golden ticket.
I've never seen Beneath the Valley of the Ultra Vixens, or Faster Pussycat! Kill! Kill!, but a quick internet search did lead to the film Up, which is another Russ Meyer sexploitation film, available in it's entirety on youtube. Ultra Vixens looks like a soft porn cross between Barbarella and Fellini's City of Women, with an unhealthy dose of John Waters. Surprisingly, that doesn't sound terrible.