Last Updated: December 9th, 2012
There's a reason that the Nexus 4 has been sold out almost since it hit the Play Store: for custom ROM enthusiasts, buying anything else is a crapshoot. Assuming that the bootloader is unlocked (or can be,) you've just got to hope there's enough adoption among ROM developers to ensure a steady stream of builds. Owners of T-Mobile's former flagship, the HTC Amaze 4G, have had relatively good options in this area, and they just got a little better: the CyanogenMod team has released official nightly builds of CM10. Owners of the older Sensation 4G can also join the party.
Both devices are supported in an experimental capacity.
Last Updated: May 21st, 2012
Update: The ICS update should be rolling out to the Amaze 4G now. Head to the Settings -> About menu to check for it.
Earlier this month, T-Mobile updated the support documents for the Sensation 4G to let users know that the ICS update would be available "very soon." Now, we have an exact date for that very soon: May 16th.
Beginning May 16, an optional update will be available for the Sensation 4G to update to the latest operating system, Android 4.0 (Ice Cream Sandwich). You can choose to download the update to Android 4.0.3 by following the software update steps.