In November 2012 I wrote a piece about. In it I complained about how Apple dumbed down the Displays System Preference to this:
To remedy Apple's resolution snubbing, I recommended a fabulous little utility called Retina DisplayMenu (RDM) from Paul Griffin (a.k.a. Reddit user "phoenixdev"). RDM runs as a menu bar item and gives you the option of selecting from 29 monitor resolution choices on the fly, which beats the pants off of four. It's incredibly handy for switching resolutions between say, reading content and a writing project that requires multiple windows be open side-by-side.
Having just taken delivery of a "Late 2013" MacBook Pro 13-inch (with) I re-installed RDM out of a renewed frustration with Apple's limited resolution options. In addition to the 11 readable "HiDPI" options, the developer also includes 18 more "scaled" resolution options that range from huge (640 x 480) to unreadable (3841 x 2160).
The developer notes that RDM (v0.2) is still under development provided without warranty or support (the source code is available inside the app bundle.) RDM is free, although it could easily fetch a buck or two in the Mac App Store.
And, in case you were wondering what 3840 x 2160 resolution looks like, here's a screenshot of six web pages open side by side -- reduced to 620 pixels wide for the ZDNet CMS. (Here's the high-res version.)