Thanks, Ira. Yes, I have currently one working Airport Express that I used to extend a Linksys WRT300N network with. That is, I
thought the AE was extending the network, but it turned out that it didn't; it only connected an attached printer to the network, but wasn't available as an access point itself. See
this post for more details.
I since learned that networks of 3rd party WDS capable routers can in fact be extended with (WDS based) Airport Extreme and Express units, even though Apple doesn't support this. Hence my interest in WDS capable router alternatives.
