Cyanogenmod has released Alpha 0 of Android 4 for the Touchpad. You can get it here:
http://rootzwiki.com/topic/15509-rel...od-9-touchpad/
Note: this is, apparently, pretty buggy, judging from the comments on Rootzwiki. Support for the camera and hardware-accelerated video doesn't work, which mean problems with Netflix, Hulu, Youtube, HBOonDemand and Skype video.
I'm going to wait for the next release -- I'm quite satisfied with Android 3.5 on my Touchpad.