Yes I have thought about this, the main issue is supply of quality long range type bullets. Not sure the investment would be worth it for the very limited number of rifle sales I would get.
I originally wanted to design my 510 Allen Magnum off from the much larger 14.5 Russian case but just could not track down a reliable source of brass. The AR-50 receiver is actually made for the Russian length cartridge, that's why the 50 BMG looks a bit smallish laying in the raceway of an AR-50 receiver, if it could ever look smallish!!!