Glad to hear that the angle iron has worked out for you. I made a little prototype with angle iron when I was testing the idea, but I was more comfortable with the square tubing. I also ran into issues with attaching the able - as you experienced. Tubing made things a bit easier for me. Call me lazy!
Interesting that you have considered adding legs as well. I have tossed this idea around too. My original sketches included folding legs but they were scrapped due to the complexity. I also considered threading a few holes into the square tubing to use to mount legs ... lots of ideas. I have considered flanges too and I think it is the best way to go. I have been drag gin my feet until I find the time to build some simple adjustable legs.
Yukon Rob: Want to race to find out who makes the removable tables first? BTW - are you actually from the Yukon? I was born in Whitehorse.
-=D