Two comments/suggestions:
1. I'd prefer a DVI-D connector (or even VGA) over the Micro-HDMI connector if I wanted to use this with a display. I've found that the bulkier, screw-locking DVI port is much less vulnerable to accidental disconnection or damage than HDMI (been burned a few times there, two "machine won't start" panic calls that turned out to be loose HDMI cables, one broken cable end, and one broken video adapter from ham-fisted maintenace personnel pulling on a stiff HDMI cable). Full-size DisplayPort has a latch, but even mini-Displayport feels sturdier than micro-HDMI without taking up much more space. I recognize that HDMI supports audio while DVI does not, but if my machine is playing audio it's likely just a fault klaxon from the stacklight rather than speakers or a TV.
2. A killer feature of, for example, Banner's XS26 safety controller (Don't panic, I don't intend to try to use your product as a safety controller, LOL) is their configuration storage device. If the device boots into factory defaults (either new from the manufacturer or after some reset image is loaded) and there's an image on the attached storage device, it will copy that stored configuration into memory and reboot. This means that my customer can keep a spare part on the shelf (for any number of machines!) and if one burns out the replacement doesn't involve a laptop, a rookie technician can replace it with nothing but a screwdriver. Bury a USB-A port (or, less rugged, a uSD socket, or less universal, a USB-micro drive port) on the bottom or even the back by the DIN-rail attachment and that will do a lot towards making this "scary Linux thing" in a potential customer's panel something they can almost treat as an off-the-shelf part like any other. (Note: I've never had an XS26 fail on me, and expect that your extended-temp eMMC is more trustworthy than most Flash drives. This is more about having a guaranteed backup and nontechnical replacement procedure than something I expect to do frequently.)