As a EE and a module/ASIC designer for the last 15 years in the telecom industry I'm quite familiar with "jitter"; jitter generation, jitter tolerance and jitter transfer. We could have a long dialog on jitter in the network but let's concentrate on IEC60958, the AES3 and S/PDIF data format rather than the Bell Core specs.

You blame the oscillator for the jitter generation in your equipment, a quick look at Digikey found that even the $1.00 oscillators are spec'ed at 50 ppm and jitter at 100 Hz was way down there with some at 100 dB down. The IEC60958 is a rather lax 1000 ppm requirement but mentions 50 ppm for precision applications. I don't think you can find a 1000 ppm crystal oscillator, none are that bad.

I checked the Cirrus Logic data sheets for their S/PDIF transmitter and receiver. The jitter generation of the transmitter is spec'ed at 1 nS. The receiver employs a PLL in it's clock recovery circuit. The 950 will most likely use these parts or equivalent devices.

The IEC60958 spec call for 75 ohm cables with S/PDIF and 110 ohm balanced cables for AES3. I would recommend that you adhere to that spec. The frequency is 3 to 6 MHz. Any video cable should work fine. A composite video cable has roughly the same requirements. Few of us will have AES3 equipment but any DS1 cable should work fine.

Here is a site I ran across and it does talk about the jitter problems in the interface. My argument is with the expensive cables which are not required. When a standards body puts together a formal standard, IEC60958, they specify the minimum requirement and design it in such a way that it works as intended. Please take a look at where the important jitter occurs, during sampling. The interface jitter is the result of slew rate limiting for noise concerns and will be removed by the clock recovery circuit.
http://www.epanorama.net/links/audio digital.html#spdif

If your CD player was dropping bits you would have pops and dropouts not a subtle degradation in sound, Similar to DSS in a storm.

I'm glad you're a DIY. I myself have designed and built a few things, power amps, pre-amp/active crossovers and of course interconnect and speaker cable. I also have built all my speakers but I used George Short's crossover expertise on these. I also bought the Model 750, I can't really compete with Outlaw's pricing. By the time you buy all the parts I would have spent the better part of a grand, and the amps themselves are already built. My sub amp is mine, all 450 watts.
Those CAT5 cables are extremely capacitive. Did you use them with an Outlaw product? They can easily cause some amps to become unstable. I can see them "coloring the sound"; they are not what you might call electrically neutral. That is just as bad as zip cable's inductance causing roll off at the upper reaches, just different. The TNT audio site kinda sucked, no info there. Here is some real DIY info. Build a Pass amp.
http://www.diyaudio.com/
More audio myths;
http://www.sound.au.com/