Very nicely, it seems, on the 6700 running WM6.
http://forum.xda-developers.com/showthread.php?t=343583
Ok, so now I really really love the 6700 again
I installed FTouchFlo_v1.4.1.CAB and HTCCube2.cab, soft reset, and started flipping cubes
All files from xda, and developed by all the great folks there, included here for ease of use. Consider it early alpha stuff, I don't think any of this is romable just yet but once it all stableizes it would make a great OEM.
Somewhat big download, 1.1MB zipped, > 5MB unzipped
How Does It Work
Swipe your finger or the stylus up from the bottom (midscreen) to bring up the cube. If you are using your finger, you'll probably have to press a little harder then you would think - mind those fingernails!. Pretty much it works like the touch.
Issues/Support 
You can tell FTouchFlo which apps you don't want it messing with, you just need to add the app (by name) to the exception list, then soft reset.
Edit \Program Files\Touch Flo\FTouchFloConfig.txt
Good apps to add to the exceptions list:
S2U2 - so cube actions don't work when your screen is locked via S2U2
Notes - so you can draw in notes with ease
So add
Exclude:S2U2
Exclude:Notes
Then soft-reset
Known problems - if you use device lock FTouchFlo doesn't play well.
Keep an eye on the actual FTouchFlo development thread over at xda:
http://forum.xda-developers.com/showthread.php?t=338143