It would be difficult, the long-tailed pair is straightforward but putting another pentode in the 'emitters' leg would be quite a problem.
If it's the antenna you are primarily interested in, look up "inductive loop antennas" for ideas. For receiving they are easy to construct, I tried one with my 100W transmitter and it generated several KV across it's ends and I had to use quite expensive tuning capacitors to prevent flash over!
Just out of interest, what subminiature pentodes to you have? I built a receiver once using EF74 wire ended pentodes and ran it off a 9V battery.
Brian.