I've used tables, landscaping bricks, patio furniture...whatever holds it! I recently made a stand out of 2x4s and plywood. No worries about heat, as long as they are on the burner stand, up off the wood.
Here are some pics of mine, from when I used all-gravity with smaller pots and then up to keggles, and then on to a single tier, with a pump.
https://www.homebrewtalk.com/f51/brew-rig-sculpture-evolution-206033/
If I could suggest anything that would make your brew day easy its:
- March Pump
- Sight Glass / Thermometer Combo
Of course you'll also need to install ball valves, some hosing and quick disconnects-if you don't already have any of them, for the pump. The sight glass makes knowing exactly what volume you have a simple task, and gives you a quick indication of temp(especially for sparge/strike water)
As for the pump...I can't even tell you how nice it is, not to have to pick ANYTHING up once its full of liquid! Just swap out hoses, and kick on the pump. It's SOOO great!! My brew buddies who used to help me transfer full kettles/keggles of boiling hot water/wort really appreciate it too!!
Whats nice is you don't have to buy everything at once. You can work up to the single tier, which is what I did. I didn't have the march pump or the stand worked out, before I had my sight glass and ball valves/quick disconnects. Of course I DID go with the ridiculous 3 piece stainless ball valves and qd's, but I knew it was going on my keggles, and they would be a permanent fixture, so why not get exactly what I want.
Funny enough, this past weekend I wanted to brew a small batch, with the remaining base malt I had, so I ended up busting out my OLD smaller pots, and doing a BIAB - starting on my stove, and ending on a single SQ14 burner in my garage. It was a breeze of a brew day(other than learning the few quirks of BIAB) but it was really fun, and kind of nice not having to set EVERYTHING up. My downfall though, is my brewstand has to be broken down, moved, and set back up to brew. Rinse & repeat. Kind of a pain, and with my stand not on wheels, I really can't do it myself. That's next on the list...after new bottling bucket setup, and a bulk order of base malt!
Cheers! Have fun with your setup! Putting it all together is one of the best parts, second only to brewing on it!!