There are two things to do if you want to completely remove this.
1. Replace the four files, BioTouch.exe, MediaHubMini.exe, AppLauncher.exe, and QuickDial.exe with the 0kb files found here:
http://forum.xda-developers.com/showthread.php?t=368269
Technically, you don't need these files to remove the cube, but it prevents them running in memory, takes a few MB.
2. Edit this registry value:
HKLM>Software>OEM>TFLOSettings>EnableCube
Set from 1 to 0
And the cube is gone!
This shouldn't have any affect on the other TFlo controls, but you may want to keep the four files available.