check these out, they may be of some use in your builds.
I've got one installed on my CarPC now (in the process of being completed) - and it works great.
Might be an option for your customers that want wifi, but can't use a PCI card.
(Of course they could use a USB stick, but I just thought I'd pass it along).
I'm happy with it so far, and there is a link to the drivers on the link I posted.
Note: You need the Pigtail too, its not included, but its on the site as well (under accessories for the module).