Trilarian: If you use a random 10 character alphanumeric password for WPA (26 lowercase +26 uppercase + 10 numbers = 62 characters) that would give you 62^10 possible combinations which from your figures would take 507553 years to crack using the Tesla S1070. With a sufficiently strong password WPA is still pretty secure.

Micro: Have you tried switching your ancient laptop back to the ndiswrapper drivers? Another thing you could try is turning all your wireless computers off, then turn off all your networking gear for 1 minute to reset it, turn the networking gear back on, and turn on just 1 wireless computer and see if you can ping that. If it works with just one computer connected wirelessly but not with multiple wireless computers it would indicate the network equipment doesn't like multiple computers connected wirelessly, perhaps because they seem to be coming through the same network interface as far as the switch and router are concerned, I don't see why it should be an issue, but I think it is a possibility.