A few years ago when I got my CNC mill, I explored this very idea of making rails for #1 rifles to sell. I asked around on all the forums and e-lists if people would be interested in buying them if they were available, for exactly the reasons you give. I got an overwhelmingly negative reaction to the idea, and even got called some colorful names for even suggesting ruining the perfect lines of the beautiful #1 rifle, which is perfect in every way. I gave up on the idea and never made any.
If your gunsmith has a way of making 1/4 ribs to match barrels, then it wouldn't be too tough to make a rail to replace the factory 1/4 rib. It needs to be made properly so it goes on light tight at both ends without any stress in it, or made very close and epoxy bedded onto the barrel to achieve the same result. Extend the rear of it back over the receiver and it'll do what you want.
This is my biggest beef with #1 rifles - how to properly get a scope on one. Everything else about them I can live with, but despite what the Ruger lovers say about the scope mounting system, it is awful. There is no way to mount a scope on one of those rifles and be able to guarantee there is no stress in it, it is prefectly aligned with the bore, it won't move, it is in the right place for the operator, etc. You can't even line ream the rings without tearing them off their puny little attachment points. But I digress.............
Anyhow, if you want a rail for a #1 call J.D. Jones at SSK ind. in Ohio. I have seen several #1s he has built with rail on them and he may be willing to sell you one. He is a sponsor on this site, so he should be easy to find.
