In fact, pick any commerical hardware product that is running any specialized or 'embedded' form of Linux or *nix and show me where I can buy the software without the hardware.

Hmm.. That would be my Linksys WRT54GS router. Except you can't buy it. It's available for free, due to Linksys having used GPL'ed software, and therefore needing to release their firmware under the same terms. I think the original post about buying was mainly because one would not expect it to be available for free.

/Spiff

And it should be mentioned that the Ekahau Engine actually works quite well for indoor positioning based on 802.11 accesspoints.

A friend of mine is using it in his ph.d. project. Unfortunately, I don't have any links to the things he's done (don't think he has much online) so unfortunately I can't be more specific :-/