I hadn't been to the Brighthand Palm forums in a long time, so I recently went to peruse. Lo and behold, there is an
incredible (and incredibly long) thread on upgrading your Tungsten battery and squeezing a lot more life out of it. A lot is made of the complexity, but if you have any basic soldering and electronics skills, it sounds simple. I am planning to replace my T|E battery (stock at 850 mAh) with a more powerful one (1200 mAh) and will try to document the procedure for the benefit of all. If you have ever cursed your battery length and you've got a steady hand and a brave heart, this is a thread for you!
(BTW, PDAparts.com has a
page with instructions for dismantling a wide variety of PDA's. Recommended if you've never been inside yours before!)