i actually just made a couple from parts at homedepot last night.
i went to the plumbing isle and they had these grey plastic barbed on one end, threaded on the other things, and then i went over to the electrical isle and picked up some grey plastic nuts, like what you would use on the end of conduit in a plastic box. I had to dremel out the nuts just a bit so that they would thread all the way onto the nipple.
Then i drilled the holes where i wanted them, siliconed the crap outta them, and screwed them in and got them tight. We'll see how well it works tonight when i get home and test for leaks.
if memory serves, i ended up with 2 complete sets for under $5