Kegtoe, there are several sites out there, a good place to start is Tejass Smokers at
http://www.tejassmokers.com/index.html They will match a low pressure regulator (or high pressure) with any btu rating you require with any length hose to go to your propane tank. They have many different parts and fittings and make custom flex lines. If you call them they are very eager to help.
Brewers Hardware located at
http://www.brewershardware.com/Burners-and-Accessories/ is another excellent site. Derrin who is a vendor here on HBT is great and he will hook you up. He has burner orifaces, thermowells, etc. and he has top quality tri clover fittings and tri clover to pipe thread adapters with great prices.
PexSupply has good prices on the Honeywell valves if you choose to go that route, along with the pilot lights for safety. They are located here
http://www.pexsupply.com/Honeywell-VR8200A2124-1-2-24-Vac-Standing-Pilot-Gas-Valve-11585000-p
Portage is also a good site for hard to find flare fittings like the female flare swivel elbow to male flare and for pipe thread to flare fittings and adapters. They are located here
http://www.portagespecialty.com/custom/Flare.html
Kladue turned me on to this site awhile back and I bought some fititngs from them.
Keith Specialty has flex lines, and the 1/4 inch aluminum tubing for your pilot lights, among other things. They are located here
https://keithspecialty.com/gas.line.htm
This should get you started in the right direction. There are many other excellent sites and vendors here on HBT that I'm sure others will chime in on.
Let me know if you have trouble locating anything specific or hard to find item. I have searched so many places for my build that I probably can locate it for you.
Good Luck!
John