The Tarp Conundrum has been scrutinized in the Lost community:

http://mswendy.wordpress.com/2008/10/14/lost-parody-tarps/

Another big quandary amongst the many LOST podcasts, blogs and message boards: [i]“Where did all the tarps come from?”. Not just a handful from possible plane cargo wreckage… but scads and scads of them![/i]

Lost is auctioning off most of its props. I haven't looked through the catalogue, wouldn't be surprised to find a couple for sale.

http://www.profilesinhistory.com/lost-auction-preview/lost-auction-preview