Hi Nate,
 
I found that tank valve in the air compressor section of Princess Auto.  I think you might be able to find it in a plumbing store also as I think they use those valves on pressure tanks for household hot water heating systems.
 
Those nice stainless hose clamps are made by ABA of Sweden and I got them from Vanagain.  Those are the clamp Ken sell with his fuel hose kit.  I bought some extras because I liked them.  You could find similar clamps locally, just look for fuel injection hose clamps, but they likely will not be stainless.  I also just got bought some German ones from the Bus Depot p/n 001 997 69 90 they are not stailess but they are nice.  These clamps are desiged not to damage hight pressure fuel hoses.
 
Pascal
'84 Westy