I would give strong consideration to color, the '10 vs. the '12, and I would also give slight consideration to any mods already done to the '10. Mods are a very personal thing, though. Personally, I would place high value on Canyon Cages, but not so much for an after market seat. Further, I would definitely not want a bike with altered PCM, exhaust, or a repaint. And I would assess no added value for a top box, driving lights, or GPS mount.
But that's just me. A different rider would have differing priorities.
All things being equal, I'd save the $3 grand, and buy the 2010.
As a matter of fact, that is exactly what I did last March, when I bought my 2010.
Regarding the extended warranty:
It is often interesting how some folks sing praises of the extended wrranty, then in the next verse of the same song, condemn the often shoddy work done at dealerships. Consequently, my own personal decision was to not extend my warranty, even though I had the opportunity to do so. I may live to regret it. Have to wait and see.
Best of luck to you, in any event.