>The whole point of "full power pistol cartridge" is versatility that it brings, along with actual handgun performance. Especially when we already have the perfection to strive for in handguns.
The problem here is that you want a cartridge that seems to be too big and strong for a pistol to handle, not to mention that you'd need a good locking system to handle it. You would most likely have to carry lighter loads for the pistol, and so you'd just complicate your supply of ammunition with the added hazard of mixing them up. A way out of this problem is to go with a carbine and a revolver. And with a revolver you don't have to worry about the size and the power of the cartridge. Now take a look at pic related: it's basically a rimless supermagnum version of .357 Magnum, it fits into standard STANAG magazines, and in theory you could rechamber any 5.56 NATO weapon to fire this. Then you are free to chop off most of the barrel without significant loss of performance. All you need is a companion revolver that is also chambered for this cartridge.