I just check on the topps website. the site lists there are 379 boxes available. March 31, 2010 at 2:35 pm CST.
A couple of notes:
I just checked the qty remaining today 4/1 11:20am est. Stands at 357. I know they added 500 last week after the supply ran dry. Does anyone know if this is the last 500, or are there 500 more? This may be it!
FYI: Also, I found that the "WackyShip" promo code shown on the uncut sheet item also works with old school boxes. Not sure if it's a glitch, or on purpose. Anyone interested in getting free shipping on Old School before they sell out should try the code.