I have four displays, and two computers — one for music, the other to run Pro Tools.
My music computer (a PC Audiolabs custom built laptop, with a 1920x1200 screen resolution (a/k/a 1080p or HD) runs my music programs – Reaper, Sibelius, Dorico. The video card allows for two monitors, my extra monitor is a 27 inch Dell, mounted on an arm. Picture is super sharp and bright and that’s actually my favorite monitor to look at when it comes to Sibelius and Dorico. I can double that second image on a 59" Samsung plasma screen, mounted overhead, though the image on such a large screen is not ideal – kind of blurry. Despite cranking up the brightness, it is pretty hard to see anything. Though sometimes I use it when just working in Reaper - it’s kind of nice to have the movie on a big screen.
The second computer is a rack mounted desktop which I now mainly use to run Pro Tools. It has its own 27" monitor, plus the same 59" Samsung plasma screen. Normally I use that big screen to display movies, run in Pro Tools. I can switch the big monitor back and forth with remote control.
Bottom line is that the 1080p LED or LCD screens are great for Dorico (as well as Sibelius) - they are huge, they can be mounted, they are compatible with most computers. Plus they are relatively inexpensive, couple of hundred $ maybe.
And, by the way, my computers are pretty old by now - 2008 and 2009 - upgrades over the past years, but they have no trouble running today’s programs. My music computer can run Reaper, Sibelius, Dorico, all at the same time, including audio, with no problems. All on Windows 7 professional, 64 bit.
Pictures of setup (Dorico is not in these pictures - I took them sometime last year or year before, before Dorico was released):