Heyyo,
Indeed, you'll wanna rtfm and try to find out how to discharge the crt first. Then you should be safe as long as you do it right that is.
Now, monitor's are pretty big, but I dunno if it's wide enough for a full atx mobo, so you might have to go with micro-atx.
Now, depending on the make, you might need to level out the inside to make it easier for the back plugins. I'm sure a basic soldering job with some sheetmetal, or weilding it on there would work too I guess, would be good enough to hold that.
Ooh, man that would be fancy for the viewsing screen to get that converted into a window, lol, dude, this would be a sweet mod, I bet a samsung monitor would be awesome since they have lots of holes in them which would light up nice with some led sticks, or maybe convert some into fan grills.. man you could do soo much with this mod, once you're done post pics! I wanna see your creation now!