I have the exact same problem, but unlike yours (or any other posts I've seen), I can not bring back the cursor in any way (moving to it to the dock, clicking outside a window, enter mission control or launchpad, etc). The only way I can get it back is by rebooting the Mini (2012 model - or at least the latest one).
The mouse is still working as I can see activity on the monitor when I move my finger around on the track pad (the dock raises, etc.)
It has never happened untill yesterday when it happened three times. The only difference is that I upgraded to the latest version of flash player. I see in other forums that people suspect Photoshop to be the culprit, and I do suspect that flash player is at least a part of the problem. Since last night I exited Safari after using the Mini, and so far the mouse cursor has been here.
chscag, I consider myself pretty much tech literate after being a *nix administrator for 14 years. I didn't find anything in /var/log when grepping for mouse, but then again I don't know the process name (or even if it is a process at all). Can you tell me if it is a process and the name of it? If so I can search the logs to see if I find anything, and HUP the process to see if it brings the cursor back.