Just get the G21sf, a 24lb recoil spring, some 45 Super Brass, a little Power Pistol and your choice of 230gr JHPs. If the 45 caliber hole at 10mm speeds is what you're after, you've found it. 1100 FPS is going to be my target velocity, when the aftermarket barrel shows up, but 1200 is supposedly possible.
This is likely what you're looking for. I know it's what I'm looking for, and I've only seen Polar bears and Grizzlies at the zoo.
This ^^^