Needed --- Recommendation on Trackball !

Hi, all !

I am setting up a computer lab for the disabled. We are looking for
equipments that might aid the disabled (mainly those who are not that
good in movement), and one of the things we are planning to get them
is trackball.

There are many types of trackballs available, unfortunately most are
made for the able-body people. I am looking for something that can be
used by the disabled with ease.

Our objective is that the trackball must be big enough, and easy
enough to be used.

One of the things we have found is the BIGTRACK trackball made by
infogrip ( www.infogrip.com/product_view.asp?RecordNumber=98 )

I want to know if there are other types of trackball similar or better
than the BIGTRACK that I list above?

If you have any experience on which type of trackball that will be
easy for the disabled, please share with us.

Thank you all in advance !!


Sincerely,
Lee