I got the sprocket for my ex 2010 DF at http://www.oldbikebarn.com/Motorcycl...?search=JTR279 and I assume the 2012 DF is the same.
I'll know in a week or two as I ordered a 35 tooth from them the other day.

You would have though that the new models would have a bigger rear sprocket but ...

I can go up my steep gravel driveway in second gear on the DF easily but the Ural and W650 both need to be in first gear.