Yes the piston version has been done, back in the time, the original BD5 A&B had the Hirth 80HP engine, A being a short winged aiming at aerobatic & higher speeds and B with long wings having quite an impressive range. A wings were quickly abandonned as they made the flying quite difficult with a significant crash rate at the first flight...
Hirth going bankruptcy shortly after Bede started delivering kit, a wide range of engine have been scratch-adapted by kit owner willing to complete their BD5.
As Bede went bankrupt too, a few third parties companies are now offering kit manufacturing and building assistance.
Depending on time I'll have, I was thinking about modifying the aircraft.cfg to simulate the BD5-T turboprop powered by a Quantum micro turboprop like it has been experimented on reality. (The tuboprop version is 3 bladed prop while the sim version will still have a 2 bladed one, only difference)
Cheers
L'iguane