It looks like Samsung are making progress with their Ice Cream Sandwich upgrade for the Galaxy S II (i9100) judging by a 4 minute video from SamMobile of XXKP1 (built on 7.12.11).
While it's clear that it's Ice Cream Sandwich running under the hood, the TouchWiz implementation looks very similar to what we saw on Gingerbread. As a result, much of the new hotness is obscured by the iClone-esque look of the Samsung launcher which is a real shame.
There's an odd border flash when the screen is touched, we presume for the purposes of testing and that it won't arrive in that state.
This has been confirmed to be a 'custom build' and SamMobile are advising against its use. If you happen to lay your hands on a copy and are tempted be warned that it will increment your Custom ROM counter, which is apparently a warranty-voiding maneuver. Performance in places looks to be ok, but they've reported slowness and plenty of force-closes from Samsung apps which aren't ready to run on Android 4.0.