I had a link from the forums at TM's site and there is/was an announcement on MVA's home page on the lower right--easy to miss. clicking it goes to
a very brief explanation. I didn't know it was fund-limited, so I count myself lucky to have gotten the credit and I'm bummed for the folks who didn't get their car in time to get the credit!
I don't know whether Maryland set aside reserves, but clearly they only earmarked a certain amount of money.
@Ven: If they're looking at extending it then that much include new funds. Hopefully they'll pump some cash into it and make it available to folks who get their cars during this gap--I don't believe there's really a time limit on applying for the rebate/incentive, so I'm sure if it's extended and includes 2013, that it will be available to anyone who got their car after the incentive ran out of funds earlier this month.