GCB et al,
I have two such rifles made by a former member of this forum, birdhunter50. both are made on 12 ga actions and handle well -- as good as my 12 ga Parker shotguns!(which is saying something!)

Beretta GR-2 action proofed at 17,000 psi was the donor for my .45-70 DR which has never been stressed shooting 300 grain bullets at 1600 fps and 13,900 psi. When you read the book by Ellis, you will see how these pressures correlate. The maker hunted deer with this rifle for 10 years before passing. His widow then sold it to me.

Simson and Co Suhl action was the donor for my .405 WCF DR in which I shoot Hornady 300 grain ammo and my 300 and 400 grain hand loads. For those worried about pressure - don't; I use VV N133 and never approach the factory stated pressures for this cartridge. I have taken a lot of game from hogs to Nilgai and red deer with it; the .405 is a potent killer of large game and with my Winchester 1895 .405 I have taken bison, cape buffalo, water buffalo and many smaller critters.

For more details and pictures, please search this forum for posts by birdhunter50.
Here is the link to the .405 double report:
http://forums.nitroexpress.com/showflat.php?Cat=0&Number=265159&page=0&fpart=1&vc=1