I have them made up by a pro audio shop (in my case ProAudioLA) with Mogami 2549 cable and Neutrik's best XLR connectors. If memory serves, a 20 ft pair might set you back $150 or so.
I've tried only one pair of designer audiophile cables, because only one manufacturer would lend them to me in that length. I invited four friends (including a composer, two musicians, and someone in the audio business) over to participate in a single-blind test. All of us found the $2,500 designer cables far more colored than the Mogami.