Bill, I have made a few half stock guns using a swamped barrel. They make real nice, trim off hand shooters. I made wooden under ribs for them. I used the same wood as the stock, but a contrasting wood like ebony could be used for accent. It seems to me, if you use a steel rib, it would have to conform perfectly to the swamp when soldered. If you clamp it into conformation,and file or mill the ramrod groove straight, there would be some built in stress, that might affect the accuracy of the barrel as it heats and cools. Then again maybe not. My philosophy is, every thing affects everything else, to what degree and is it a positive or a negative, are the questions I ask myself. Good luck!
Robby