I have felt that temptation as well, and have resisted. If anything, I'll go for the J-Tek bar end shifter. At present I am still running my Nexus-8 with its stock grip shifter, which I have mounted on the straight part at the top of a drop bar. To do this, I had to cut the bar in two (on the right side, near the center ferrule) and fit an extension inside it, which is held in place with set screws. I used a narrow bar that I didn't have any other use for, so in the process turned a 38 cm bar into a 46cm bar (that's an improvement!) but the set screws are an imperfect solution. They have worked their way loose once before, and riding it yesterday I noticed the bar was squeaking. That's never a good sign. I will tighten them again.
Perhaps the thing to do is to epoxy bond the inner tube into the outer tube (permanently). The set screws are just not going to work - the bars get flexed to much.