I Understand what you said, don't really know any riggers.
For miscellaneous and the real deal try:
http://www.paragear.com/
I enjoy working with them as they are straight forward and professional.
My original 550 cord supply has changed if you decide you want new I have a few
others for future use....get use to that change thing in textiles
For fabrics not sure what you might use but have good contacts now and some materials in bulk .
Lowy is a good place when prototyping, when you get something solid you'll want some more affordable sources:
http://www.lowyusa.com/webbing/nylon-webbing
Bally Ribbon being one:
http://www.ballyribbon.com
You can catch some odds and ends just by checking different places periodically, I think "Sportsman's Guide" has some para cord in their military surplus section.
The challenge is buying the right quantity for the right price. 5,000 yd fabric runs go for $25,000.00 and up. It is getting more challenging finding mil spec rolled goods but they are out there.
Lots more happy to help.