This is an overlay of the two logic boards using photos of the iFixIt teardowns (with a grain-extract filter thanks to Gimp) and there seem to be no real connection issues. I placed my order for a logic board but I was still a bit worried so I got board (hehe) and decided to see if there were any significant differences. For the life of me, I can't see why this 'upgrade' wouldn't work, and the iFix it forums have instilled some modicum of confidence in me… I decided to try it! I was actually amazed that there wasn’t more information about this kind of thing on the internet (with all the menial stuff like hacking your xbox and tricking out your iphone). I heard from a repair shop guy on e-bay who said the upgrade wouldn't work (but I think he was just trying to sell me his repair services). The iFixit teardowns and logic board replacement guides for both models (2011/2012) seem identical along with all of the tech specs about the wattage/voltage/etc.

I found a decent deal online but I couldn’t find anyone who ever tried it.

figure that one out) and the upgrade from USB 2 to USB 3 ports.

This is a slight edit considering I browsed through my old answer and even I found it a little confusing: I had a logic board accident with my early 2011 MBP, model a1286 and was thinking of replacing it with a Mid-2012 (non-Retina) board for the CPU/GPU boost (I'm a gamer and a Mac user.

A1286 logic board lcd connector