Butch Searcy was building them on Ruger Red Labels and Browning SxS shotgun frames. Not sure if he still does or not.

Much too much skilled work for my feeble hands, so I can't build one myself.

I've heard a rumor that Ruger is going to build a double rifle, on thier new Red Label Side By Side frame. However I'm not even sure if that gun is out yet, so it could be many more years before a double rifle comes out. That seems to be how it is lately. Announce a new gun, get a lot of hype built up, and then wait months or years untill there is enough pent up hype to ensure good sales.

So I'm left waiting for the Russian made Baikal .45-70 double rifle to hit our shores, and I think I'll be waiting a while longer too as now that they've cleared Washington's red tape they're the hold up is in Russia at the plant or politics somewhere. But for ~$500-600 they're something to look foward to. Little rechambering and maybe some new wood and you might have yourself a nice piece of work.