Looks like my mini has the HDMI issue that others have reported on the macrumors forums as well as here.
Mine exhibits the blank screen/snow issue ONLY when the HDMI port is used. This happens with HDMI->DVI adapter and also with pure HDMI cabling.
With the same screen, mini and DVI cable this does not occur.
This is a fresh Mini 2012 Server i7 model.
Do I need to report this in an official capacity somewhere (this is only the second ever apple hardware fault I've encountered in twenty years). Should I just be patient for a possible fix (as I don't need the hdmi port
Well I can happily say that since the 1.7 update I have no blank screens or snow. I have re-calibrated for both DVI and HDMI and now they match up and contrast/brightness are ok.
For me at least this has cured all the display ills
(to recap my system is a 2012 Mini Server 2.3 with 16GB Crucial kit and running intel 240GB 520 series SSD with the second 1TB HDD). - happily running 10.8.2 with 1.7fw.