Right you are...Magpul just announced new 10, and 15 rnd mags for the AR. Seems they have been in the design phase for a while due to sales to Calif. (10 rnd max.) or other sub-30 rnd rule states.
See the below link for pics and more details.
The Firearm Blog Magpul Announces 10 And 20 Round PMAG
2013 will be an ugly year for gun laws methinks.