If I need a custom built sock (try to find a stock sock for a 6pc . . .) I go to Clear Creek Fishing (https://www.clearcreek.net/Rod-Bags_c_31.html). Brenda will build a sock to your specs (length, no of compartments, etc.) for the same price as their OTS socks.
Both products are excellent quality and they ship fast.
I have purchased several from this seller. They are very basic. Note you need to be careful about specifics. He sells bags for both graphite and bamboo rod customers. Bamboo rods are often 3 piece plus a spare tip. Ye Olde English Fly Shop eBay