Codeworkx decided to release an alpha build for CM9/AOSP ICS.
Here is the link.
[ROM][IML74K][4.0.3] CyanogenMod 9 experimental Build [UNSTABLE][12-26-2011] - xda-developers

I flashed this Monday just to test it. It seems a lot better than the leak from sammobiles, faster more stable, data works etc.
If your network supports NITZ then its a no go (I am on three UK and it worked ok for me so I guess they dont support NITZ)
The deal breaker for me was video playback, it didn't support any of my avi files I had so I restored my backup. If it wasn't for that I probably would have keept it on longer as other things seemed to work quite well.