I've got my retina macbook pro but I'm disappointed a tad. There is no 1440x900 resolution option. The most comfortable res. I found is 1680x1050 but I was wondering if there's some sort of hack for the 650M, or will NVidia update to fix this?
Would this help? Sorry I'm away from my computer so I can't experiment. http://www.ehow.com/how_8446265_custom-screen-resolution-windows-7.html
I am trying to get accustomed to 2880x1800 now. It takes some getting uses to as the icons are pretty tiny. I will try the hack too maybe later on.
Windows has DPI scaling. You can set it to the maximum resolution, and then increase the DPI to make elements appear bigger whilst keeping clarity. Performance shouldn't be an issue; the rMBP's a powerhouse, so long as you're not running it solely on battery.