The devices you make do not scream "touchscreen user", imho.
I think 7-8" is acceptable for 1024x768 (4:3 aspect ratio but too small for scope though imho) and 1280x800 (16:10). I personally found that 1920x1200 made Scope eminently more usable. Especially with large modular patches and devices like the Solaris, otherwise I was having to use larger virtual screens and mouse around at the edge of the screen to reveal hidden areas of a device.
My scope PC now has a 1440p (2k) monitor, and tbh that's overkill for my workflow. So a 13-14" 1080p mounted on a VESA mount & arm seems ideal to me for studio use. I am sure those same units will fail when abused, so I was thinking of an AJA or something akin to that without the recording possibilities, perhaps. Ie, a device that can capture and display many more input types including SDI (serial digital interface, BNC cable), as I sometimes work shows where I support other artists.
Anyway most of the DSLR mount style monitors have inputs that are often compatible with closed circuit cameras for cheap security and car uses, as mentioned. This is why they still often have RCA & S-Video ports. Here's an example of a 1280x800 monitor, similar to the one I have on my desk:
Neewer F100 7-inch 1280x800 IPS Screen Camera Field Monitor Kit.
These units will always advertise a resolution up to the highest supported for whatever dsp is driving the thing, but 4K on an 800p monitor is going to be awfully difficult to read or make out tiny onscreen elements, as these are typically just doing a bilinear scalar function on the input image buffer.
Here's a slightly better unit, more comparable to the Black Magic or Atmos units I am referring to as being the type that will be truly road worthy. Note this fellow has a 1080p native screen and supports SDI:
FEELWORLD FW703 7 Inch IPS 3G SDI 4K HDMI DSLR Monitor Full HD 1920x1200
Note that I would consider this unit as a program monitor, and it's a good budget option for 1080p native uses there. I am unsure whether I'd recommend it to you for the pixel density reasons mentioned above. I think you'd want it mounted lower in your visual range, just on the edge of your workspace, where you can easily read textual elements & etc.
Here's the Black Magic "SmartView" series for HD & 2K, you can see why they're considered road-worthy. They are built for rackmount, and metal housed with thick plates over the monitors themselves. Small flying objects shouldn't pose much of a problem, and they mate well with the video switchers you can see below them. The 4k version (
on another page) is closer to 10" tall
Then there's AJA and Atmos, companies that make DSLR & studio monitors with built in recording and/or switching control.
The Shogun-7 from Atmos runs $1300 USD and supports 4K & a bevy of color modes for film & video, along with high bit-depth files directly stored on the monitor unit. The 5" version called the Ninja was very popular 4-5 years ago. They also have larger units, but note the studio monitors can run $3000-4000 from them.
You don't need anything in the last 2 paragraphs imho, not for scope surely. But just to be aware of what many of these smaller monitors are attempting to imitate, using recycled panels from older laptops and commercial uses. 48% sRGB coverage will likely matter even for scope, meaning a cheap TFT panel with limited contrast & brightness is being used to make a $99 panel, whereas the counterpoint here uses very high end 12-14 bit panels (or 10-12 bit with FRC + dither), and there are many extra functions built in to analyze and scope the inputs you're feeding signal to...