Managed to find a regenerative receiver based on the 12AT7 tube. I've
been told I can substitute one of my 12AV6 tubes without a problem, so
that looks promising.

I have some twin triode tubes, as well. (6FQ7, 6BZ7 and 4BC8) I've been
wondering if I couldn't make some one tube receivers with them. (Use
one triode for regeneration, the other an amplifier.) As for the rest
of the tubes I have, I'd be willing to sell or swap for parts I'll
need.

Ralph