I seem to be the only person able to work very happily at 2880x1880, haha. I love having a lot of screen space and, while 1920x1200 is far easier on the eyes at first, it just seems that everything displays too large for me now - even on a 15" screen! I'm feeling very comfortable at 2880x1800 and love the amount of space that I'm provided with without sacrificing, for my eyes anyway, readable text.
On the topic of this thread, I like SetResX. It has a lot of resolutions to pick from, including the obvious 2880x1800. It sits as a lightweight menu bar app for quick switching and it costs nothing. However, I've noticed that some resolutions (oddly, including 1440x900) display as if they were on a normal screen when you switch to them from SetResX rather than System Preferences - not Retinised at all. But 2880x1800 looks just fine and this app should suit your needs.