All I can think of off the top of my head is to get an M61-HCRI-LL and put it in an MD3. Then get a delrin battery sleeve.
Not really a practical solution, but an HDS High-CRI clicky with a (limited run and long out-of-stock) 2xAA battery tube would work :)
solarforce make a 2xAA host as well?
You don't happen to HAVE one do you? My RA high CRI only has the 123 and the 17670 tubes. :(