The main reason the AVAtrix doesn't have HDMI is that when we began design of the 1166 (part of the AVAtrix head end), DVI was the dominant connector format - HDMI was a bit of an upstart.
Transmitting component video over Cat-5e is easy - it can be sent long distances, in a balanced line configuration, and easily gain-equalized to correct for loss over those long distances. Doing the same to HDMI and DVI is harder, partially because those formats are distance-challenged anyway, and partially because there are so many conductors inside HDMI/DVI cable.
Let's do some math - HDMI cable has 19 conductors inside. Cat-5 has 8 wires, twisted into four pairs. Two Cat-5s equals 16 conductors.
Existing HDMI over 2xCat-5 solutions don't used a balanced line configuration, because to do a balanced line, you need two copies of each signal. That would take 38 wires (5 Cat-5s) to do. A non-balanced solution is vulnerable to noise, and a 5-cable system wouldn't be practical, so right now we're looking for another solution. Also considered are HDMI's continued problems with compatibility - inserting a matrix into the mix makes for some problems on some sources/displays. (There are some 2 x Cat-5 solutions that use 10gb Ethernet, which seems to be a more reliable way transmit HDMI over UTP).
So I guess our stance is that "we're working on it". Just remember that HDMI/DVI play by different rules than Component, and that means that solutions that work nicely for component may not work at all for HDMI. Keep checking the website!