I ordered a 1440p 27" monitor to use with my new MBP. I got a mini-DP to Dual Link DVI powered adapter. It will be interesting to see how the HD 4000 fairs with a 1440p screen. I think it will be fine as I can run a 1680x1080 external monitor + the 1280x800 monitor fine right now. The 27" will be around 25% more pixels, but I don't think it will be an issue.

As for gaming at 1440p...