You could probably use pretty much any tablet with a client app for the DVR - just turn off the power saving functions and plug it in. Don't even need things like bluetooth, GPS, etc - WiFi should be all the connectivity needed, which should be just about any $99-and-up Android tablet out there. Trickiest part will be finding a way to mount it to the wall, but there are plenty of car mounts out there that could probably be adapted.
Take a look at our Awareness Monitor, 10.4" and 15". Built for mobile applications, people are using in a variety of ways, VGA, HDMI, or two BNC inputs. If you can get DC voltage to power it...we may have exactly what you need. Has metal chassis, vandelproof screen protection: see red SPECIFICATION SHEET far right side of webpage, or email firstname.lastname@example.org.
I'd be leery of putting a lithium battery in a wall, charging 24/7.
"designed for commercial use where running 24/7 is crucial"
Lenovo tablet that uses micro USB to charge will turn off charging once the battery is 100% and temp goes up... it will turn off charging drain completely and wait till USB is unplugged and replugged. Fyi.. Went through 3 different models as touch screen controls for CompleteControl.
IPVMU Certified | 02/19/16 08:38pm
I just finished a two week test of a Samsung Galaxy Tab 4 running Hikvision iVMS-4500. Never crashed or hung up the whole time. I can not say how it will last plugged in for extended times. It was however sitting on a charging cradle for the whole 2 weeks. For ~$130 I was quite impressed at how well it operated with 15 channels on almost the whole time.
If this one isn't too big, it may work: https://viewzusa.com/security/ipm_home.html