While not a military action, you should take a hard look at the Brno 601. A customized 601 is the scout rifle that is featured in Cooper's "Art of the Rifle." If you can find one with the pop-up peep sight, a scout rifle could be configured from the Brno with much less effort than starting with a military Mauser. There was one on Tradex a while back, not sure if it's still there or not.
As Ardent said, the Ruger 77 comes ready to go as a scout rifle, but if you wanted to upgrade to a McMillan stock or add a stripper clip guide these are minor expenses compared to starting from scratch with a bare action. But I suspect you already know all that, so I am curious what it is that you want to build that would be better served with a military action than a good quality CRF action, designed for a sporting rifle.
If you are set on the Mauser brand, Tradex is your friend.
Edited to add . . .
Andy makes a good point. An expensive custom rifle is probably only valuable to the fellow who pays up front. The resale value might very well be less than an off the shelf gun, unless you find a buyer who is looking for that exact thing. I know you've admired my 602, but on the used market its a thousand dollar rifle and nothing more, and then only if I refinish the stock where the finish has worn leaving uncolored fiberglass exposed. Naturally this rifle is worth far more to me, because the sum of its parts makes it something special to me. Yet none of my gunny friends think much of it, complaining the recoil is too fast and too hard, and they universally dislike the scout scope after a life time of conventional scopes.
