I'm heading back to the US and I planned on doing the UPS mail in passport and get it back in a day or two with a new visa.  However, the person at the embassy told me it takes 10 days and that seems like a long time seeing as it always used to be a 1 day turn around time.  Anyone done this recently?  

Most Thai workweeks seem to be only a day or two lately so that sounds about right for LA Consulate if they observe both US and Thai holidays.  

This is the official web site information:

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Apply by mail

Applications are usually processed approximately two weeks not including mailing time. However, lately we have received more applications than we normally receive at this time so processing time could take longer. When submitting an application by mail, a self-addressed stamped envelope with sufficient postage stamps is required. Metered stamps should not be used, please use a regular stamp only. ( Recommened using USPS Express Mail Flat Rate / NO FEDEX without a FedEx account, NO UPS without a UPS account ).

 

http://www.thaiconsulatela.org/service_visa_detail.aspx?link_id=26