I have a Babson/Surge vac system. I use belly milkers and can milk 2 goats into 1 bucket. I can set up a total of 6 goats to be milked on this system.
It can be built with used equipment pretty easily although I would recommend goat shells and liners if possible.
I can't post pics of what I have since I have temporally lost my camera cable to the computer but here are some pics and you can probably find what you need pretty easily:
Here is a link to the basic system I have: http://www.ebay.com/itm/COMPLETE-PORTABLE-MILKER-BUCKET-DUAL-GOAT-SHEEP-MILKING-MACHINE-PUMP-MILK-COW-/251074462828?pt=LH_DefaultDomain_0&hash=item3a7534446c#ht_1826wt_698
This person lives near me so I brought up my parts and he set everything up.
I bought a vac pump and had it put on wheels. It was in good condition, heavy but it does move! It is a 3/4 hp machine. That was $250 locally--didn't have to ship it!
I use the Surge belly milkers, you can probably find them on craigslist or on some old dairy farms. Here I can get them for about $35 each. You may need to buy lids and pulsators, not sure how much they are. A rebuild kit is $45 for each milker. I have the instructions to rebuild if you need them. I can copy and send them to you.
Milk line and air line can be bought at most fleet farm stores or dairy supplies.
My milkers have shut off valves on the hoses, like in the second pic on the ebay ad.
The main reason I chose this set up over the others is that it allowed me to milk more than 2 animals at a time (although my goats have not yet agreed to this set up so we are at 2 animals at a time), and I can also milk my cows and sheep on it without having to do much, just different belly milker pails for the different animals.
I am changing over to the tall bucket system until I can one day get a real dairy parlor and pipe system. In the winter it is difficult to carry the belly buckets over the snow drifts!
It is easy to clean up and all in all I have liked it. Since I had everything from the start, it cost about $500 to get the thing put together--pump on wheels, cleaned, and set up properly, all milker buckets cleaned, rebuilt pulsators, new lines, airhoses, inflations.
PS: If you do get belly milkers, make sure you don't have the kind that have a seam in them. They can collect more dirt and yuck and are in general, not safe.