They are not very easy to come by....
Don't look for any kind of PC Monitors, your best bet is to look around for "Multimedia monitors" or Presentation monitors - ones that are to be used to display in public places or in corporate presentations.
I have an old Hantarex thats 28" that will do 800x600 and 1024x748 interlaced (just - it needs some TLC....).
Look for old NEC presentation monitors - not sure if they go up to 1024 but they also go right down to arcade resolutions and are on of the best all round solutions if you ask me.
They all tend to be built like tanks (mines around 50kg) as designed for transport as professional kit.