It is called internally the HTC Doubleshot, and, although we've heard about it before, some additional specs now reveal that it is not an HTC Sensation version for T-Mobile, but a totally different handset.
first dual-core handset with a side-sliding QWERTY keyboard. The keyboard might be similar to the one on the T-Mobile G2 that you see in the thumbnail, which we found to be excellent in our review.
The HTC Doubleshot will sport a 1.2GHz chipset, and, given HTC's traditional ties with Qualcomm, it will be the same third generation dual-core Snapdragon that is in the HTC EVO 3D. It is not faster than the other dual-core chipsets, but returns pretty decent benchmarks nonetheless.
The handset is also to have a 4" display with 480x800 pixels of resolution, and run Android 2.3 Gingerbread.
It is taken with the handset by an HTC employee in Washington, D.C., and dubbed "HDR test toward Virginia" on Picasa. So, yes, obviously some HDR post-processing capabilities will also be in play on the dual-core handset with a physical QWERTY keyboard.
The HTC Doubleshot is supposedly appearing in July on T-Mobile's network, in your choice of two different colors.
source: PocketNow & Picasa