HDMI distribution is probably the worst way you could go for something that needs to be robust and road-ready.
HDMI was designed as a consumer
level interface that would be used in semi-permanent installs over cable lengths of a few feet. While there is "pro-grade" distribution equipment out there, it's expensive and frankly I don't like the connectors. Long distances can be a problem as well. Audio is a moot
point because your
Mac Mini won't embed audio if you're using a
HDMI adapter, so you would still have to run a separate
line for that.
The industry standard for distributed video is still
RGBHV and
SDI. In your case you're probably best off going with
RGBHV unless the budget is there to go digital. At lower resolutions the quality over long (300'-500') distances can be very acceptable with good cable and amplifiers. Many
LCD TV's have HD-15
VGA inputs on the back so you could input directly into the TV's without needing adapters, and use common computer displays as well. The cables and distribution gear are available from a number of different manufacturers, and is common enough it can be rented in pretty much any major city if you need to supplement for a bigger job.
As far as RGBHV-CAT5 baluns go, they are an OK solution that can allow you to pass both video and audio down one inexpensive cable, but they don't provide the greatest video quality and
skew becomes quite apparent over long distances. They are an increased cost, and the ones that work the best are also the most expensive, almost to the
point where you can
purchase SDI converters for only a little
bit more.
Which brings me back to
SDI. Specifically HD-SDI.
SDI is a professional
level standard that is currently most commonly used in broadcast, but is seeing a growth in the touring and corporate AV markets as the equipment comes down in price. It is by far the best way to go for long distance runs where picture quality is important. Audio can also be embedded easily into the digital stream, then decoded on the other end. The cable used is RG-6
coax rated for use with digital signals, and can be distributed using amplifiers, or often daisy-chained out of one device and on down to the next.
We switched over to HD-SDI distribution for our corporate gigs a few months back when we upgraded one of our seamless switchers to a
unit that has HD-SDI output and have had great luck with the Black Magic Design mini-converters for "breaking out" of
SDI and back to analog YUV or
HDMI when we need to use a older piece of gear that doesn't have
SDI inputs like a
LCD TV. So far we have had great success using them and the quality of the
image is fantastic.
Black Magic makes a converter that takes
DVI and a analog audio input and converts it to HD-SDI, which could then be converted back to
HDMI and analog audio at each TV using one of their mini-converters, then daisy-chained to the next display. The DVI-SDI converter is about $400, and each SDI-HDMI converter is about $500 so it does get expensive pretty quick, but it would offer the best picture quality and the easiest setup/
strike.