Well... what exactly is your goal? To have one just to have the "only" AK in .458, or to build a "special kind of big game rifle", or just a cool CQB rifle?
If you're just looking to have one, you shouldn't be hindered by the fact that you can't get a reamer. I'd have to say that if you go that route, you should just buy the AR upper, or a bolt action barrel, or whatever, and get the barrel sleeved to fit the AK action. Sell off the rest of the parts on gunbroker and call it done.
I agree that they are working themselves out of a job, because of "proprietary" reasons to make more money. IBM did that with MCA architecture, and ISA-based PCs ruled the world thereafter. IBM lost market share and their arguably dominant status of PCs at the time.
If you're looking to cover the performance that this caliber covers, then you hit it that there are plenty of Wildcat carts out there that could meet the performance. You may want to look into the .50 Beowulf cartridge which would be my choice... more widely accepted and is no longer what I could call "wildcat".
Then again, you may be able to find something in the .40 size that would meet the performance this offers. Heck, maybe even a .35 round with the right case? I know there is a pretty popular .35 remington conversion called .35 whelen (I think) that is a heavy hitter. Maybe a .45-70 bullet? Dunno.
Have you looked around at the reloader Wildcat forums? What about Clymer? They have plenty of Wildcat calibers. You're talking about $400 to get dies and such for reloading. What about brass? I'm not even sure how they resize something into that shape!