sjoko2 swears by this stuff, and I am about ready to buy a used snake of it that came out of another studio:
http://www.gepco.com/
You can request a quote via email from them. Their prices are VERY low. I reviewed a quote sjoko2 got from them for some custom assemblies and was shocked at the prices. He claims the cable sounds much better than Mogami Quad, which is pretty nice sounding wire, and is cheaper to boot. Go check it out. I believe they will sell direct to you.
Other options are to check with local electronics stores. Not Radio Shack, but stores that carry small electronic parts. Usually, they can custom order Belden, Mogami, Canare, etc......
If $5 a foot doesn't scare you off, the Monster Studio Pro 1000 (for mic level stuff) and Studio Link 500 (for line leve stuff) is amazing sounding wire. Some here will talk trash about it, but I did a blind listening test with another engineer that put the Monster stuff against every major "quality" brand of cable, and he picked as his favorite EVERYTIME the Monster cable. It always had deeper lows, more articulate mid's, and sweeter high's than all the other cables (his description, and MINE!!!) and controlled rise/fall times in the audio much more naturally than all other brands of cables. Of course, something like Mogami Quad is much better sounding than Horizon, but it is still shy of Monster SP and SL wire. But, you pay for that sound, and you pay dearly. I would recommend having a stereo path of Monster, and use Mogami Quad or the Gepco for everything else.
Good luck.
Ed
i made a profit selling it because i had more leftover then i originally paid for.