Basically any new monitor that you buy now which are 1680x1050, 1920x1080, and 1920x1200 are HDCP compliant.
While 1680x1050 monitors can display 1080i/p video (1920x1080), the video resolution will be lowered to "fit the screen". This will cause a decrease in video quality.
Always go to the manufacturer's site to find out info like this. There is no need to call them. It only took me 1 minute to find out, then again I didn't need to check since I already knew the answer.