I own a rooted Nexus 7 16GB running on 4.2.1. The default interface (stock ROM) is the phone UI. I have read mods and a certain app that changes the DPI to enable the tablet UI.I would like to have the phone UI primarily but I want certain apps to run in the tablet UI mode. Is this possible? If so, how?
Maybe you should look into this ROM, however I cannot guarantee if there is an availability for the Nexus 7.
It is hybrid, meaning, that individual apps can change from tablet mode to phone layout mode on the fly. It is open sourced and is available on github.
Thanks to eldarerathis for supplying the linky to the N7 Version found on XDA.