we bought some cheap 21 inch monitors (97%srgb, cheap ips) and removed their stands. This way they fit in a small flightcase. If they break it's not a big deal. In stead of the monitor stands, we use cheap guitar stands to support the monitors on the table, which fold down easily. We use them for fast jobs, where we know the camera's because we own them, and use color presets on them. Since we know our presets (we already did 400+ jobs with some cams) color accuracy is not so important anymore.
Here is a pic of the setup with the guitar stands:
https://www.instagram.com/p/6H2ylmMmH1/The particular model is: JS-AG75 from jamstands. You can buy them on amazon, but I think we paid them cheaper. They fold down to something you can put in a small peli case where you would typically store some cables, and it looks pro on the desk. Additional positive point: we always set up our power distribution box inside those stands.
If we have bigger productions, we take some mid range 24 inch Eizo's to the job. That's necessary because they are 100%srgb. Properly calibrated they're not far off from a rental proper 'tv monitor' which costs 10x the price. They do have stands, since we also use them in our office for editing and take a lot of space in the van. Finding a suitable case is also a problem, so we use the cardboard factory boxes untill we find a better solution.
For the best image quality and color accuracy, I learned that you better invest in proper calibration tools (spyder) and use the rest of your budget for the monitors. I calibrate our monitors monthly, and have the spyder always in a toolcase. A properly calibrated cheap monitor is still better to judge your image on, then an expensive one with the wrong settings.
For size: we always use dual or triple HD monitors. We once tried a bigger monitor (27 inch) and it's more convenient to work with, but it's too bulky for fast deployment in our opinion.
Fast job: 2x cheap monitor
Important job: 2 cheap monitors (for gui and multiview) + 1 eizo (fullscreen program).
Very important job: 2x cheap monitor + 1 eizo + rental professional monitor.
For us size and weight are important factors: our gear + crew needs to fit in our Fiat Doblo at the end of the production. That's why we don't buy big or heavy material. Time to unpack everything, drag it to the workplace and into your storage is also valuable. So in my opinion: smaller is better.