spaniel
Both Lee and I have completed the project that you are thinking about. It is a relativlely easy conversion, if your were to do it yourself you would need a drill press, a machanist vice would really be nice, a collection of two-three drill bits and a 10/32 tap, with the necessary hardware to turn the tap.
Other than that if you have a machine shop in town or the vicinity they can complete the project in a few minutes time.
I would suggest a couple of things, I beleive the Lehigh vent liner to be the best of the vent liners offered, and when you drill the iniatial opening to fit the plug in make the opening 1/16th larger than the diameter of the diameter of the vent liner flange. If you look at my example you can see I made the same size as the vent liner. Later attempts were made larger. The larger cavity helps reduce blow back.
Last resort send it out here and I'll get it done for you...