Back in....oh I'm not certain how many years ago, nearly a decade? More? My parents used my college savings to purchase a Tad Taylor MCS "porcelain" trailer sight unseen and have it delivered across the country! My MCS had become so severe the only place I could be was in a stripped down bathroom, and even there was still having severe reactions.
The trailer saved my life, and I lived in it for 8 years or so.
Now I no longer need it and am looking for someone to sell it to! We paid 45,000 for it. It uses
CeramiCircuit heaters. PM for further details if you like.
I will say, it develops mold in humid environments. Anything near the coast will. The advantage of this trailer is pretty much everything's metal, so there's nothing for the mold to eat. Which means it can be cleaned thoroughly. It's been addressed with vinegar,
extremely high heat, and shock ozone treatments.
I currently live in a minivan, and wear a chemical cartridge respirator (a.k.a. gas mask) when out of it. It took a couple months to make the minivan tolerable, and it wouldn't have been for me years ago.
Best of luck in your search, I know it's not easy!