It is now available and I got mine in! The bezel is different, but the body is the same. The Ultra does get noticeably warm very quickly (within 15 seconds).
X300 on left, Ultra on right
Ambient light
X300
X300 Ultra
X300 on left, Ultra on right
X300 on left, Ultra on right
Ambient light
X300
X300 Ultra
X300 on left, Ultra on right