Hi Southpawtact.
The three floodiest torches I have in my collection are the Elektrolumens EDC MC-E, the Olight M21 and the Peak Rainier P7.
All three do a fantastic job, but the EDC MC-E is by far the best 'wall of light' torch I have ever used. It's a real credit to Wayne at Elektrolumens. I've run it for 30 minutes at a time and it gets warm but never hot.
The Olight M21 with the OP reflector is great also. It's bright, reliable and runtimes are pretty good. Can't go wrong with it. It's probably the most versatile of the three as it has multiple modes whereas the other two are single mode only.
The Rainier I mentioned (even though it doesn't run on 18650's) because it's also a fantastic floody torch and punches out a freaky amount of light for such a small torch. If you run it on primaries you get around 110 lumens. Stick in a rechargeable and you get the initial blast of 450 lumens (claimed) until it settles in around 350 lumens (claimed). I don't doubt it reaches around 350 lumens. People freak when they see this little torch putting out so much light. Only thing is it does get a little warm after a while, but never too hot to handle.
If I had to recommend one, it would definitely be the EDC MC-E. Tough as nails, bright as hell and simply a thing of beauty.
I'm going to get myself into strife here, but if you were to consider other battery types, I'd also suggest looking at the LED Lenser M14 (yes I know, LED Lenser is not the rockstar brand like some others) but it is pretty damn good. It's regulated, has multiple modes, runs on 4 AA's, is reasonably sized, and of course it can be a mean thrower or a great flood torch. LED Lensers still have one of the better focusing mechanisms around. Not quite 400 lumens but at just a click over 200 lumens, it's a pretty good, bright, focusable, versatile torch.