maybe for you, but not for me. 800x600 was still very cramped and the first time I felt I could comfortably do development was on a 21" Sony CRT at 1600x1200, though that was pushing the monitor resolution-wise and it lost a bit of sharpness compared to lower resolutions.

Also, I'm unsure as to how the monitor type would have any impact on the screen real-estate available to the OS. If the OS is rendering an 800x600 screen, then there are 800 pixels of room available horizontally and 600 vertically, no matter the screen technology.

Given a 32 pixel size of an icon for example, there's would be room for 25 icons horizontally with a 800x600 resolution but 50 icons on a 1600 resolution. The screen technology does not factor into this at all.

What I do give you that it's probably possible to drive a CRT monitor of a relatively small size with larger resolutions because pixels can be infinitely small, though, as I said in the beginning of the comment, at some point you will get issues with sharpness and things become blurry.