Just noticed Miculek shooting an S&W 686 Competitor in one of his videos. The point of that model is to be able to adjust the mass in the barrel lug as desired. You could even, by stacking light weight spacers, position the same amount of weight farther forward or rearward, if you weren't using all the weights, so you could affect the radius of gyration independent of the total weight. Pretty neat.
The bored out lug got me thinking. Suppose a person likes GP100s but doesn't like the nose-heavy feel of the full-lug barrels. Maybe, rather than just cutting it off and making a round barrel ahead of the ejector shroud, which would require remarking the caliber for it to look right, it would work to just bore it out. Make it hollow to take a lot of the weight out. Unlike making the barrel round, drilling the lug would be a simple, single machining operation and require little to no refinishing (at least on a stainless revolver). At least, if you have the precision capability to get the hole drilled right. Whereas, the lug could be removed and the barrel made reasonably round with a saw, grinder, files and progressively finer abrasives used by hand.
Drilling would keep the meaty full-lug profile and look, and keep it fitting snugly in more common holsters. There's no reason you couldn't make it like the S&W Competitor, but that would be a little extra work. Could also go with tungsten weights that way, if you were so inclined and had the money to get it done.
Just a brain storm I thought I'd leave here.