I've seen this packaging used by many companies, specifically in mobile equipment, automotive ECU's, marine, and other harsh environment applications. I doubt all these manufactures are making the packaging for themselves, so it must be some sort of standard format that I can purchase.
To describe the packaging, I would call it a rectangular box that's a solid plastic housing on 5 sides but one, that normally has a single PCB counterpart that slides down in and has a 'cap' on one side of the PCB. Sliding the PCB into the until the cap 'clicks' into place gives it a watertight seal. The cap usually has 1 or 2 Deutsch style or other automotive connector. Additionally the main housing usually has 2 tabs off it for an M8 / 1/4" bolt to secure it to a flat surface.
Any info on this would be appreciated.