A year or two ago, I bought a dummy load kit at the Texas City Hamfest. It's basically a bunch of 1K 3W resistors, a mason jar, a couple of perforated metal disks, and an SO-239. Some assembly required. I made some changes to the design, replacing the SO-239 with a BNC connector, and adding BNC connectors for sample and AM envelope detector outputs, and it's now done. The guy who sold me the kit gave me way more than 20 resistors, though, so I have a bunch of 3W resistors left over, not to mention the fact that I misplaced the resistors so I bought even more.