I wasn't able to run another instance of VS or SSMS from inside the simulator, but I was able to launch  most other applications, such as IE, Chrome, Word, and any of the Windows Store apps. But launching Outlook caused a problem since it was already running in the desktop session. I ended up having repair my Office installation as a result.  Sad

Anyway, I guess this is one way to run a Windows Store without it taking over the entire screen (apart from running dual monitors, of course).