My thoughts on this...
If you already have/have had a 7mmRM and you like the 7mmRM, then just keep shooting the 7mmRM. It's great cartridge, and I've been using it personally for 22 years as my main deer cartridge. Never once let me down.
If you are completely new to 7mm magnums and starting from scratch, and you want the new hotness, but something that will put down nearly identical ballistics to the 7mmRM, but in a newer shinier package... Go with the 7mm PRC. It's already proving itself to be a great cartridge, as well.
I'm not a fan of SAUM/WSM cartridges...Especially in short-actions, because like has been said already, WAY too long COAL to try to use any sort of good high-BC bullets in a short-action without a massive and likely-problematic amount of jump to the lands.
Now, that said, you could always do a SAUM/WSM/Sherman Shortmag in something like a medium-length action. I think there's companies that offer those in nice aftermarket actions, but don't know who does right off the top.
Also, to top things off, there is no such thing as "inherent accuracy" or a "forgiving cartridge"... Those are bullshit terms created by marketing teams to push sales for new cartridges they are offering. Any cartridge in any gun can be accurate with the right set of circumstances...Like a reputable gunsmith, good barrel, good work performed, good ammo, and a good shooter.