Here's the problem with the question: you need two monitors to do this right. One for the GUI, and one for the video signal. You really can't do this correctly using just one monitor, as PP's built in monitors are designed for content monitoring only, not accurate display of the signal.
You will also need a way to get that 3k signal out to the second monitor, and that likely means an AJA breakout box, which start around $1,000
3K monitoring with Adobe can be done with the 2.5K or 1080P monitor without the I/O card because Adobe will ratio scale it to 1080 Res anyway for preview. You have to change the Preview codec with adobe to change the Preview resolution.
remark to the replies:
ad 1) I'm using the HP ZR2740W since nearly one year, no problems
You need to calibrate the display, e.g. http://spyder.datacolor.com/display-calibration/
ad 2+3) nothing to add