If you believe him, you can buy them for 10 thousand euros on eBay.
Be warned that the nails are in poor condition and would need to be straightened and de-rusted before you could reuse them in a carpentry or woodworking project. Link (Thanks, Patrick!)
Mark Frauenfelder is the founder of Boing Boing and the editor-in-chief of MAKE and Cool Tools. Twitter: @frauenfelder. His new book is Maker Dad: Lunch Box Guitars, Antigravity Jars, and 22 Other Incredibly Cool Father-Daughter DIY Projects