Any of these quality gun makers shouldn't have a problem putting the large bolt handle on a ruger. The only question may be if it interfears by hitting the stock or anything like that (which I doubt).
As FLEA said about HD rifles, I would go with one of the shops that does it right. You do not want the bolt handle tac welded on, it wont last. The pins are good. Tac-ops actually chops off the old handle, then drill and taps a threaded stud into the bolt handle, and then threads the bolt knob on. So you literally can screw the knobs on or off. If a better contour knob shows up sometime, just un screw the old, put on the new. (Though they only currently have one bolt knob shape)
MEL