This page lists hardware donations requests by X.org developers.
Developers should list contact information, what hardware they are requesting, what subsystem the hardware will help with, and any specifics about what they plan on doing with the hardware in question.
Note that this is not an official X.Org program, and that there is no guarantee (all care, but no responsibility), that your hardware will be used to perform a specific task to completion (it may simply be too difficult).
The format should be something along the lines of the following:
M: <Email address>
H: <The hardware requested>
C: <Comments, including what it will be used for>
H: USB tablet device, preferably with support for as many odd buttons and tools as possible.
C: Currently the support for tablets in xf86-input-evdev is exceedingly primitive, and hardware to use for testing and development purposes would be quite useful.