HTC Desire S and HD owners won't need to buy a new phone to experience the Ice Cream Sandwich and Sense 4 goodness of HTC's latest offerings. Xda-developers forum member proxuser has ported the One V's ROM to the two phones, giving users the (almost) complete One V software experience. The initial port was posted several weeks ago, and proxuser has been steadily updating it since. Despite having gone through several rounds of bug fixes, there are still a few things that don't work: you won't be able to use the camera on either the S or HD, and the S doesn't support USB tethering or use as a wi-fi hotspot.
The custom ROM does, however, include Android 4.0.3 with the latest version of the Sense UI, along with up-to-date apps and even 25GB of free space on Dropbox. The response so far has been very positive, but you'll still want to make sure you're comfortable installing custom firmware and have a backup on hand. If you're interested in installing it, you can head over to the Desire S or Desire HD forum threads to pick up the necessary files.