27-inch MustHD 2560*1440 Field Monitor with HDMI input Tally Focus Assist Marker False Color (http://www.musthd.com/products/27-inch-musthd-25601440-field-monitor-with-hdmi-input-tally-focus-assist-marker-false-color-79.html)

How good are these for Production Monitoring esp. judging Lighting on Chroma shoots ?

If you are in that price range already, I'd be looking at Flanders Scientific.

Get a smaller size, better display model like this:

FSI 10bit 17 Inch Native HD Broadcast Monitor (http://www.shopfsi.com/CM171-p/cm171.htm)

Yup, Flanders is the way to go unless you have huge bucks.

We have the 17" and it rocks. Lots of features including scopes.