If it's still a possibility, you might want to try having your recommenders send your letters via overnight mail (FexEx, etc.) All three of my LORs were sent within the last 2 weeks, and all of them were processed very quickly - the last two were processed the business day after they were sent (!), and the first one (sent 11/2) only took about 4 business days.
I don't know why LSDAS would give priority to letters that were overnighted - I should think that they'd put them in the queue with the other letters recieved on the same day. But it looks like that's not the case. (I also used the "new" LOR forms with the bar codes, but I don't know if that was a factor or not.)
If you've been waiting a while, I'd see if you can get your recommenders to overnight a new copy. I paid the overnight fees in advance for all of mine.