The biggest problems with a setup like that are Reach (too far = tired quickly)
and Obstacles. (when you wail on the TB and slam into a joystick, monitor glass...etc.)
My suggestion, is to make a pull out drawer Control Panel that rests under the
main control panel. Make is sturdy with heavy duty guide rails/supports... and
a locking mechanism.
Since Trackballs are not that deep, the drawer depth wont need to be huge,
and the CP drawer height shouldnt be too bad at all.
(just make sure you leave maybe 1.5ft distance from the center of the
trackball to the edge of the cabinet. So that if you roll very hard - you
wont slam your hand into the cab front)
The other option, is to mount the TB's upside down on the far egde...
then, simply lift the control panel up, rotate it 180, and set it back down.
(youll have to make sure not to twist the cables too much tho)
And finally, one could make a vertically rotating double sided control
panel.
As said, I dont think you will be very happy when you have to
over-extend your arms to play for any durration over 5min. And
the lack of room to really wail it, also will present problems for
certain games like MM where you need to go as fast as possible.
Hope these ideas help.