maybe your local junk yard. where you at? I know of a junk yard here in weatherford that has a few old chevys...can check it out for ya.
factory ones or clear ones? Classic parts or LMC sell the factory ones. aftermarket clear as said e-bay.
On a side note here, clear marker lights are only legal to use when using amber bulbs. Which most users don't abid by and why they aren't commonly found.
