It would be interesting to see if they work.

And as for shutting them down, they need to change their web page to acknowldege Speedplay's trademark. Other than that, there's nothing impermissable for marketing a product for use with another product that you don't own.

Ton's of people market accessories, such as covers, for iPads that are not authorized by Apple.

If they try to market it through Ebay it might violate some Ebay terms of use, but they do not appear to breaking any U.S. laws. ( particularly if they clean up the web site to cover their ass on the trademark issue.)