Yep, the thermal issues with SS are the expensive piece, it's a lot easier to remove heat using airflow when the differential is 400 degrees F, a lot harder when the differential is 100 degrees F or less. More mass, or other methods (fluid based heat exchangers for example) are often needed. I might take on the challenges to build one, there are pre-built pallets available now that solve some of these issues, and dirt cheap power supplies are also available. Used to be that you had to combine 4-8 devices (do I dare call them "pills"?) to get any power, now a pair can get you 2KW. Amazing.