Folks with the OG Galaxy Note (the world version GT-N7000 -- the one with the home button) are in for a treat, as SamMobile has a leak of 4.1.2 for the big gal. Be aware that this is a testing version, and may not be up to release standards. Known issues are the lack of S-Pen features.
The list of enhancements and what is working is a good read though. According the the source, here's what to expect.
As for when to expect this one to become official, the sources think that will happen near the end of he year or early 2013. There's no word on when we may see anything for the US versions of the Note. For more instruction and the download links, hit the source link below.