I just did the same thing on my own Gov't model. Bought an Essex Commander slide, and cut down the barrel I had. I had seen some comments on this board about the difficulty in doing this, due to the fact that some of the dimensions are different between the Gov't and Commander frames. I cut down the dustcover on the frame, and cut back the forward area of the frame rails, and inside the frame where the rear of the recoil spring sits. Can't think of what that area is called right now.
As to how well it works: I parked the slide Wednesday, and put it together yesterday. I only fired about 100 rounds through it, but did not have a single malfunction. Put ball and SWC rounds without a hitch. I am going to get some HP to see how that works. Overall, I am quite pleased with the results. It didn't shoot this well ever before.
What I want to do is slightly different from what JRTex did in his pistol. I want to use the 2 different slides (4" and 5" slides) to a common frame which I want to retain as standard-sized frame, i.e. no modification whatsoever thereat. I have invested so much in my government sized frame so I'm not inclined to do another modification anymore. Will appreciate your advices.