This week, I bought a Palm TX, from a friend of a friend. I've been able to boot linux on it, using hackndev howto. I hope that I'll be able to research more fronts now (kernel, applications, performance, etc.), because Palm TX is expected to have a working USB support (so that I can telnet on it :-)) and because of the different capabilities of Palm Tungsten E2 (PXA 255, 16 MB main memory, 320x320 + input area) and Palm TX (PXA 270, 32 MB main memory, 320x480, no input area).
In my quest to make the USB controller to work without messing the rest of the system, I've found an interesting reference about GPIO configuration for linux ARM. Devices may be activated/deactivated with GPIO ports and, as described in TE2 forum thread at hackndev, USB requires controling GPIO 53.