Schiit has some shorter ones for stacking at a good price:
http://schiit.com/products/pyst-cables
If you believe in premium cables, all of the custom cable shops make these as well and you have plenty of time to get them made before you get the amp.
Do note that the Pyst cables are very stiff and may not be the best choice for many situations. They're designed to run between the Magni/Modi and could possibly be too short and stiff for use with other equipment.