The Nexus One is still out there and although it is generally considered to be outdated, it still hangs tough with in today's smartphone environment. After all, when the Nexus One was released a couple of years ago its specs were far beyond any phone on the market at the time.
Google hasn't released a version of Android 4.0 for the Nexus One, but it looks like someone is giving it a try. The result isn't great, but isn't bad either. As you can see in the video he has it running on a Nexus One. Perhaps Google will see fit to port Ice Cream Sandwich to their Nexus One loyalists.