I have some very large (by my standards anyways) furnaces that could be used for bail out style furnaces. I believe they're made out of insulating kiln brick, 2600F. They range in size from 30" across by 20-30" deep to 60" across by 30-40" deep. They do not have lids like you'd think. The outer casing is either SS304, SS309 or one of them is inconel 625. They are very well built and were resistance heated. Free for pickup in Akron, OH. Forklift and dock on site. The smallest of these is probably 1100 lbs, the biggest, probably 4K. I'll get pictures this week.