oh my this is beautiful!! can't wait to see where it goes! love the name ~
here's a script someone else posted on another thread: http://pastebin.com/typctTFd. stick it on your main camera and set the height variable to 144 and it'll force your screen to mimic that resolution!
other tip that i'm trying for the first time - not quite sure of the pros/cons yet - is i'm making a unity unit equal to a pixel. so when i import my sprites, i set my pixels per unit to 1, and then i don't mess with any scaling! this also means that as long as the x and y positions of my sprites are integers, they should be pixel perfect! i do have to make sure my sprites are exported with even numbers for dimensions though (instead of 7x7, i would have to do 6x6 or 8x8).