"better" cable = "better" connector? the problem is probably not the cable but the terminations. I've installed many HDMI cables that were inexpensive ($1/foot) and never had a problem, but ultra cheap crap can skimp on the connectors and not place nice with panel jacks that are within spec

Shielded cable doesn't affect the noise floor or ground loops in digital signals. It DOES affect whether that transmitted 0 or 1 makes it to its destination as the same 0 or 1. Dropped samples would sound like pops and clicks or "digital" noise (white noise-ish). BUTT, after the DA conversion a computer becomes a hostile environment for analog signals, because almost no computer HW is shielded, so all kinds of RF and EMF can interact with analog cables even outside the case. On top of that cheap sound cards don't output balanced signals that makes it even easier to pick up noise.

the Crestron ADMS does all that and more, plus it can control everything else in the house (lights, remote rooms, IP Dishwasher etc..)

Euler already has that one

don't forget you'll have to modulate the two channels if you are going in through the RF connection

Masking systems have been used for years in courtrooms and banks to keep people from hearing things they shouldn't. When the lawyers approach the bench, they turn on the system and it allows them to have a private conversation while the jury can't here it. Masking systems are also used in conjunction with paging/background music systems, and if it was installed properly, you don't even realize that you are listening to filtered white noise. No fancy "sensors" or crazy DSP (ok,just a little DSP).