I recently started a new project, to build a short, light, double fifle, "on the cheap". I picked up a pair of .303 barrels, in as-new condition, that came from the 1910 Ross rifles. I turned them to a very light profile, and threaded the shanks 3/4"-32. I have a Laurona 20 gauge that I used to make the monoblock from. I have so far, bored and threaded it, and also threaded and soldered the barrels into it. Although the Laurona is an inexpensive gun, and is poorly finished, most of the poor finishing can be rectified during the build. I have already refinished the stocks and recut the checkering. The gun has most of the desireable features that one looks for in a host gun for a double rifle, ie:
Double underbites
Greener crossbolt
Bushed firing pins, and nice tight, close-fitting pins
Action bolsters

I have sent some photos to CaptCurl for him to post here for me. Will add some comments when he's done that.