Which custom cables are available?
From what I know,
With the bass adjustment
Toxic Cable has 4 options. You have to ask them yourself. http://www.toxic-cables.co.uk/
Beat Audio cable has a lot. Check out http://www.beataudiocables.com/
Effect Audio has one option, Thor 8 wired. http://www.effectaudio.com/upgrade-cables/iem-upgrade-cable/thor-copper-8w-occ-spc-iem-upgrade-cable-by-effect-audio.html
Plus Sound Audio has a few. Haven't tried contacting them for info. Check http://www.plussoundaudio.com/
With out the bass adjustment
Double Helix Cable. http://www.doublehelixcables.com/