I got such switches from my friendly dealer for the "old" LxD and PxD models, ready in tailcaps with a larger rubber cap.
Well, it wasn't just that great with the UI which stays unchanged of course. As I am used to the reverse clicky, I press down for activation. Cycling through modes means switch off first, then cycle and pressing down again at the wanted output. On the other hand, you rapidly change modes to high and stay on momentary. Light off, a second later you decide to switch it on again and land in SOS mode.
No, for me they just aren't of good use, I preffer to stay with the original switches and use a real Tactical if I need it. The smallest I have is indeed the T10C, but I preffer the longer ones, for a one-hand-use, better for my large hands. The Jetbeam E3P also has such a switch, more lenght and is quite heavy.