Here is a site that sells those inlets found on race cars but not the round ones you have used, also have hoses for sale, 12 foot of the same ducting for 10 bucks versus 2 4-foot sections.
LINK:
http://www.pegasusautoracing.com/adv...ryID=BRAKEDUCT
If you have a chance please measure the diameter of the brake ducts you used, both the outer diameter including the flat flange and the inner diameter of the actual opening, it would make searching for parts much easier, thanks.