I answered that entire argument with myself by simply saying:
What does the studio use?
The way I figured it, a studio isn't going to pay $300 for 15 feet of wire when they have to run several thousand feet minimum to get their work done. Yet they are producing the very content that I am viewing on a DVD, so any degredation from bad cable was already done at the source, there's little I can do to improve it.
Turns out, they tend to use some good quality RG-6, around $0.35/foot. I chose to go with Canare L5-CFB, a good RG-6 cable. Lots of folks also use Belden 1694A, a slightly better RG-6 cable (almost the same price). Lots of studios wire with these. Terminate with some good RCA connectors, not a F-RCA adapter.
For a 12 foot svideo run, I'd recommend you break the svideo line into two coax cables, and recombine it on the end. bluejeanscable.com sells svideo breakout cables, as well as premade coax bundles. They use the same stuff the pros use, at a good price, so I see little reason to go higher.