Since Northwoods Sugarworks is no longer selling them, I put a unit together to go along with an original Lunchbox unit we bought last summer. I originally used a Coleman cooler, but it turns out the Igloo that Northwoods used has depressions on the inside of the lid that are really nice for lining up the fittings. Overall it was pretty easy to put together.

installationpartssupply.com has the pump, but the model number has changed. Their catalog number is G80-E022A, (my invoice says "Formerly G58"), they have it for $73.69. I'm sure other models would work, but these are designed for bag-in-box drinks, so there are a lot of places on the web that have them & the related parts & tubing. The John Guest fittings are available on Amazon, but I could only find them in bags of 10.