The trackball is 2". The lip around the trackball isn't very high - less than the width of a quarter. That would probably be the hardest part of installing in a panel. Other than that, I'm sure it's possible. The buttons would have to be removed for it to sit flush under the panel. The case does come apart. They also are used but in really good shape.
The guy has 21 of them. I could probably get them for around $15 if I buy them all. Please reply if you're interested as I really don't want to sell 20 on ebay.
I'll probably buy one just so I can throw it off the roof.