Price tracking web site dealmac notes that Dell in the U.S. is offering the Canon EF 17-40mm f/4L for US$539.25 including shipping, and the Canon EF 70-200 f/4L for US$502.49, including shipping.
The dealmac entry provides instructions on how to get these low prices when ordering through Dell's web site. The offers expire on July 28, 2005 at 7 AM ET, or after 10,000 uses. It isn't apparent whether the lenses are Canon USA warranty versions or grey-market imports.
Update, July 24, 2005: Dell in the U.S. is now sold out of both lenses.