Sounds like I found out what the problem is with the mac mini. The mac mini's antenna is on the bottom side, and since the mac mini is ALL METAL, if you put another piece of metallic equipment underneath (e.g. a Newertetechnoloy ministack 1TB external HD) of the exact same size as the mini then that restricts the mini RF capabilities. I inserted an empty cardboard box (e.g. Parallels Desktop 7 empty software box) under the mini, with the external drive on the very bottom, and the mini on the very top, creating a 2 inch gap between the two.
Results: the trackpad can now operate as far as 18 feet (beyond that I have a hard time seeing the cursor on the screen). I can even pair it from that far away.
So... Apple Management:
Please acknowledge there is a Hardware issue with your mac mini's antenna design.