You might want to get a rats tail file. Those tubing cutters leave a small lip on the pipe that might interfere with certain bar ends. Key word might. Not 100% sure it will interfere, i just know they leave a lip
Brother, do I cut a lot of tubing! There are a variety of ways to cut steel tubing. My preferred method is to mark the point where you want the cut to be and tighten a small hose clamp around the tube there. It will automatically center itself and gives you a good square edge to mark all the way around the tube with a fine Sharpie. Then, clamp the tube gently in a vice with padded jaws and using a sidewinder (right angle disc grinder) with an abrasive cutoff wheel, simply cut the tube a small amount at a time, rotating the tube in the vice, and continue the cut. Be sure to leave a little extra for smoothing out the cut with a bench grinder or hand file. A cutoff wheel, however, will load up with aluminum and stop cutting, so is not preferred for this application.
A pipe cutter will also work, at least I think it would work on the aluminum of the renthal bars, but never having done it I can't be sure. Generally, I use a hacksaw after marking it as above. At least it takes less time with a file to smooth out the cut compared to steel.
Most importantly, fit your controls to the bar before cutting! Don't assume removing a certain amount will give you what you need. Remember the fabricators number one rule: "It's a helluva lot easier to remove material than add it." Less expensive too.
If it has already been done, it is safe to assume it is possible to do it.
On the other hand, if it has not been done never assume it is impossible to do it.
------- Rob --------