Yet first place on that '10 Best Roofing Materials for Warmer Climates' list is occupied by 'white metal roofing'.
It comes down to your 'noise of rain on roof' tolerance I suppose - I love the sound. I too have lived under corrugated steel roofs in the tropics, on the north east coast of Australia - Mackay in my case. I don't recall the noise of rain being an issue, even in the wet season. Perhaps it's a problem with inferior (thin) metal roofing, like your average khon Thai would use, and/or with that mostly flat stuff.
I live under concrete tiles now, in Sydney. It can get warm here - in the low 40s (celsius) lately - that's pushing 110F. We had one of those days just this week, then a "southerly buster" (cool change) in the late afternoon. We still needed the aircon on in the bedroom overnight though, the clay-brick walls and concrete tiles radiated heat long into the night.
As to metal roofing in Thailand, Australia's Colorbond (Blue Scope Steel) has outlets - there's one in Buriram that I have already visited (they say they get a lot of Aussie Farang customers
). Seems they call the corrugated stuff 'Colorbond Thermatech'. But regardless, Colorbond is cut to size, so you don't have the joins to worry about, and comes in various thicknesses. Better security too - the thief cannot lift a tile to get into your ceiling space.
Interested to hear of your progress anyway Pink - hope you keep us updated.