I have a 2012 MacBook Pro (non-Retina) running Lion and two Magic Trackpads - one for work and one for the home office. If I'm away from the office for too long (say a long holiday weekend), my office Trackpad won't reconnect to my MBP when returning to the office without removing the pairing and reconnecting it.
This is a real pain because unless I'm on my couch, I use my MBP with the lid closed and an external keyboard. So I need to open the MBP on my desk and use the built-in trackpad to reset everything before I'm back to working.
And now the one at home is doing it and I'm starting to get a little cranky.
Is this something I've brought on myself by using two Trackpads? I've named them "Home Trackpad" and "Office Trackpad", and both show up in the Bluetooth settings.... choosing "Connect" just doesn't do anything, and I have to unpair/repair to get it working again.
What I'd really like is a USB version of the Trackpad - no pairing, no batteries. But I doubt that would be aesthetically pleasing to the Apple engineers.