I'd like to see a light, handy, little single shot rifle in the .50 McMillan FatMac. Close to 20,000 ft-lbs of energy: 750 grain bullet at 3425 fps.
Or, a rifle I read about a while back: 2 ga., loaded with exploding(!) bullets. One of the really hairy-chested early ivory hunters used one such.
Note: I want to SEE one, hold it, possibly even OWN it, but, no, I have no desire to fire one. Be happy to watch, though.