If your compressor does not hold pressure, I'd check for leaks or a faulty regulator. Tennis Machines would probably have the parts since they bought out the remaining parts. I read somewhere you can replace the compressor with a pancake comressor you can get from Harbor Frieght for $40 or Home Depot.
If you want swivle clamps, the first machine that comes to mind is a Prince Neos 1500, to go with the Prince theme. But the mounting on the 1500 is more similar to the 5000 and 6000. Though not impossible, you could make an adaptor plate to mount the brake system/turret to your machine.
Here is the Brake assembly from a Prince 5000.
I also have this from a Eagnas Flex 740. If decide to use an Eagnas TT.
E-mail me if you want this piece.