Has anyone seen a hot plate, with the heavy coils like this photo, anywhere around Bangkok?

You don't mention wattage - should be able to find normal 500w units but if not can order in about a week from here:

https://www.aliexpress.com/store/product/Burner-Electric-stove-Hot-Plate-kitchen-portable-coffee-heater-Design-l-Hotplate-Cooking-Appliances-220V-500W/2406010_32727458962.html

Thanks for that.

I am a bit concerned with the term "ring shaped heat pipe". I'm afraid that the coil, itself, may not be the actual heating element. 

Have a look in Big C, they got quite a few different models.

Thanks.

The ones I have seen at Big C have covered burners. Most of these are heated by spring type coils that tend to be short lived.

I looked all over Klong Thom with no luck either.