Try here ("Bicycle Thin Cards") - they're not made on the same stock though but I shouldn't imagine that would be a problem if it's thin cards you are after.
Thanks for that link Cardza, just what I was looking for. I already have a small stock of standard Bikes. But I have a few ideas of my own for some tricks I want to try out, that need thin cards.
*EDIT* Cardza, Had a good look. That site is a treasure trove of goodies! Thanks!