HTC have confirmed today that the Desire HD will receive an update to the latest version of Android, Ice Cream Sandwich.
The Desire Z and Desire HD were announced at he same time and cost a similar amount. The Desire HD has received numerous updates. First to Gingerbread then has been updated to Sense 3.0 and will now get an update to ICS and Sense 3.6.
The Desire Z has only received one major update and that was to Gingerbread.
I understand HTC's decision to not update the Desire Z to Sense 3.x due to hardware limitations. However following the announcement of the HTC One V and the leaked RUU's that are available, HTC now has a version of Sense available that is suitable for the Desire Z.
The Desire Z is still the only worthwhile Android device with a hardware keyboard available in most parts of the world. My opinion is that because of the lack of new devices with hardware keyboards the Desire Z still has a large user base for a device that is 18 months old due to there being nothing for them to upgrade to. HTC should acknowledge this by providing its loyal users with an update.