Sourcing Parts for CO2 Manifold

Fabricate it. If I picture your project correctly, all the fitting will be 1/4" npt. Your wyes, shutoffs, gauges, regulator input/output should all be this common fitting. Any good plumbing store will have copper pipe threaded (male) at 1/4". If unsure ask for "nipples" (secrectly you've always wanted to ask for that ). Add a 1/4" "tee" to branch out, . . . then cap-off the last opening with a 1/4" male plug (may have to add a coupler or two to make it all fit). Even good ole HD or Lowe's will most likely have 1/4" nipples in multiple lengths, price will be cheap. A little pipe tape, a leak check, and you can add "Manifold Maintenance" to your resume.

 

How bout McMaster-Carr

http://www.mcmaster.com/#manifolds/=sgpcar

 

You can re weld your existing manifold. If you want to add three more lines you can get another three way and connect the two by drilling and taping one of them.

 

For manifold blocks from harbor freight you should look at the quick connects.
http://www.harborfreight.com/air-tools/air-tool-accessories/3-way-uick-coupling-manifold-68195.html

Or you can hook together several T's to make enough ports if you dont want to use quick connects.
http://www.harborfreight.com/air-tools/air-tool-accessories/14-female-brass-t-connector-68197.html

personally Ive changed out my whole co2 system to quick connects. I have one line from my tank to the back of my fridge, another from the inside of the fridge to my distribution system, and individual quick connect lines to each keg. i love it this way as it allows me to swap things super easily

 

What ryane says.

If you want to go simple, a series of tees/nipples/shut-off valves will do the trick. You'll need a threaded barb on one end for the gas inlet and a male plug on the opposite end. No need for stainless . . . CO2 is non-reactive and copper and moisture play well together.

The idea of qd's for the tank supply is also solid, I can swap a tank out in under 5 seconds. My interior connections remain threaded as they rarely (never?) change.

But if I had a six-keg keezer and routinely won medals with sours I would have multiple pressures available. A simple 3-stage secondary with 3 wye outlets will give you six hook-ups with three different pressures. You'll take a one time hit on price, but it sure makes life in the keezer more pleasant. Other than win medals with sours that is what I have done . . .

 

Foxx equipment, if you can convince them to establish a commercial account. You will not beat the price.
Plan to buy some other junk you have been meaning to get and place an order. Really, you will not beat the price, and the service is great. They take credit cards.
Cheers
Edit, I will note again, you will not beat the price. Foxx will get you the equipment you need without headache. But they do not serve the GP, go in knowing something and youll be set, just like McMaster Carr really, more so even.