HTC seems to be working on Sense 3.6 to accompany Android 4.0 for its existing devices like Sensation. One of these early official firmwares has leaked online and has been posted by Paul from Modaco on his forum.
This RUU is primarily meant for developers only; however if you would like to get the taste of Ice Cream Sandwich and Sense 3.6 on your Sensation or Sensation XE, at least two custom ROMs(1, 2) based on this release are already out on XDA. Both the ROMs are said to stable and include all the ICS goodness.
This leaked RUU seems to be the first build to appear with HTC Sense 3.6 because the earlier two (