The German company ERNI offers some DIN rail mount enclosures:
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The one pictured on the right on the first page is interesting because it allows you to design a PC board with common terminal block and just slap it in the enclosure. The last page shows another view.
How many companies make enclosures like this? Are there any US manufacturers that offer these?
Me and a colleague spent a lot of time with a search engine just to find these and we are not finding anything quite this elegant.