You can bid on the Project Runway fashions. These are the actual clothes featured in the challenges. It has been speculated that the reason that Kirsten didn't want to use her scarf was because she would have to give it up to the auction.
Just for fun I did a search on eBay for "Vintage Hermes Scarf" and there are currently 59 scarves up for auction. I'm sure there would have been a lot more if I had tried different parameters. Then I did a search for "Napoleon Scarf" and there are nine! All Hermes. I don't think it would have been very hard for Kirsten to replace her scarf.
Here is a link to a 2002 GenArt Fashion Show featuring Kirstens's bathing suit designs as well as an interview (about halfway through the clip.) Just click on the little movie camera icon in the window. Trust me, it works.