This is a little side step to your topic but I was just looking to make some balanced cables & came across the Neutrik NCFXX - EMC series. They have built in RFI/EMI blockers built into the connectors. Trying to decide which cable I want to use with them.
Also, Performance Audio is a great on-line store for any type of custom cables needed or in bulk. You can build some cool speaker cables thru them. They have a large assortment of Mogami types/series.
I bought Mogami Platinums XLR's from Sweetwater & really liked them in my 2ch set-up. I really liked them. They are kinda pricey for Mogami though. Majority of their bulk cable is cheap for what you get.