Hi CT - I'd like to provide some information that I think might be helpful regarding the idea that it is a third party software conflict.
I owned a mid-2012 MacBook Air that I recently sold to a family friend. I too experienced the disappearing cursor issue during my ownership of that computer. Before I sold it, I reformatted the SSD and fresh-installed Mavericks using the recovery partition.
The new owner just reported that she has experienced the disappearing cursor issue. As I helped walk her through setup, and asked her just now to verify the third-party software in her Applications list, I can confirm she has only the following third-party software installed:
Epson Event Manager (printer software)
Microsoft Office 2011 (Excel and Word only, along with standard files installed with Office 2011)
I had Office 2011 installed during my ownership, but not the Epson software, so this instance of disappearing cursor is almost certainly not caused by the Epson software. Note that the new owner does not have anything from Adobe installed on the machine, not even Flash Player.
Based on this experience I am skeptical that it is a third-party issue, but maybe it would be helpful if new replies in this thread could confirm whether or not they have Office 2011 installed on their machine?