Modding an X5 for rechargeables

So I've been reading up on all this flashlight stuff (wow, like everyone I never realized so much was out there!) and I've decided on either an Inova X1 or X5 depending on money. The X5 is probably what I'll go with though. However, no rechargeables worries me because I'll probably use it quite a bit. So here is my question:

I've gleened from a few places that it is unregulated, which means it just uses resistors to set the current through the LED. If it's true, then shouldn't I just be able to change the resistor on the board to set a new operating current that is safe for the LEDs? Rechargeable 123 cells look like they're 3.6ish but is that a loaded voltage or an open circuit voltage? I would think that I can just change this resistor to account for the 0.6V difference and have a nice rechargeable X5.

What do you guys think? I'm trying to think before I leap

I've never disassembled my X5T, so your question is a little beyond my knowledge. I do know that the tube diameter is pretty tight and I cannot fit my protected R123 in it. I would be cautious about running 2 unprotected R123. Good luck!

You may want to have a look at this thread:

https://www.candlepowerforums.com/threads/93444&page=4