Accessibility for person with a motor disability

Hello all,

To help people with motor disability, I'm trying to search what software 
and technologies exist on GNU/Linux.

Sorry for the cross-list post but I don't know where to ask for help.

I've already found the following software:
* dasher: for writing text
* eviacam: a head tracking software
* mousetrap: another head tracking software
* onboard: a configurable on-screen keyboard

My questions are:
* Do you know if there is eye-tracking software?
* Does head-tracking is really efficient?
* Do you know if there are other useful application?
* Do you know how to use the numeric keyboard to move the mouse on Mate?
* Is there a mailing list or forum where there are people with motor 
disability using GNU/Linux?

Best regards.
-- 
Alex ARNAUD
Visual-Impairment Project Manager
Hypra - "Humanizing technology"