phew they were backed up really badly - i sent one and it was processed in exactly 13 days (counting weekends) and i sent another the was processed in about 30 days (also counting weekends). i wrote them an email at some point, and they said that it usually takes at least two weeks to process letters, and when they were backed up, it took even longer.
All of mine were sent over a month ago and none have been processed yet. I am somewhat less than pleased.
I'll be able to tell you very soon if the overnight thing works. One of my recommenders sent me the LOR instead of LSAC, so I overnighted it to them on Monday. I tracked it and saw that it got there yesterday morning. I'll let everyone know how long it takes to get processed. It will be interesting to see if it gets done any faster than another LOR of mine I know got there last week sometime.