Saw this this morning.

On a Magnum length Oberndorf square bridge in .280 Ross.
The only issue I could see with this gun is the bolt handle alteration and of course that it is in .280.
The action magazine is very tapered (just as my Gibbs 280 is) so choices for a rebarrel using the stock magazine may be limited to .375H&H. Maybe a 404 but pretty sure a 416 would need a wider box at the front.
The bolt dace would need to be redone in any case since the .280 has a bigger rim dia. than most.
A good deal IMO

http://www.gunsinternational.com/William-Evans-Custom-Mauser-in-280-Rimless.cfm?gun_id=100351672