Modding an Inova T1; possible?

The Inova T1 has always been a favorite of mine for its incredible build quality, grenade grip, kroll switch purely cylindrical form. Can't think of any other light quite like it. Awesome handfeel. Anyway, the T1 was discontinued. I have 2 of them, one with an xpg and the other with a luxeon led. The circuits aren't too bad; reasonably low pull of current on high, around 600-700ma.

Can anyone mod these? They are notorious for their difficulty in opening. I would imagine a strap wrench at a minimum.

no mechanic, but imho nothing else but "freeze-pop" possible;
at least without getting visible marks
(result: damaged driver, normally)

I really like the T models. Somehow the checkerering and overall "make" are great.
But for useful modding (other led, 18650 instead of whatever original battery, ...) all the models that generally could make a base (T1, T2, T3) offer not enough space inside, or are too small a diameter, or ...
... therefore no mods at all
? :thinking ?

Actually, I've been using 16650 cells from Orbtronic. At 2500mah, I think that the power supply is adequate as is; no need to bore out.