Sleeved Cables. Not extensions.

If you mean you need extra cables I would contact OCZ support?

http://www.ocztechnologyforum.com/forum/forumdisplay.ph...

If you meant you wanted them sleeved but already have them then:

http://www.performance-pcs.com/catalog/index.php?main_p...

No, I'm looking for something that is 'like' a BitFenix Alchemy extension cable, but I want something that is a full cable. I've found this ( http://www.corsair.com/power-supply-units/psu-accessori... ), but I need one that is compliant with my power supply.

Corsair has colored individually sleeved modular cable sets

http://www.corsair.com/power-supply-units/psu-accessori...

Yes, I linked those, but as far as I know, they won't fit my OCZ ZT750W PSU.

Correct, and as far as Im aware what you are wanting does not exist.

Make your own sleeved cables:

All you need is the following,

Tech Flex

http://www.parts-express.com/pe/showdetl.cfm?Partnumber...

Zip Ties

http://www.parts-express.com/pe/showdetl.cfm?Partnumber...

You should be good to go then.