I have a situation where I have 3 building that are over 1000 ft apart and have no wired solution we can plug into (and no line of site) for sharing files. Does Cisco provide a wireless Internet hardware solution where 3 buildings can share files securely such as VPN? 1 Meg up and down would be ok, but I guess that depends on the service provider.
Recently, I've come across the D-LINK DIR-450 that uses a PCMCIA card with 3G and other wireless Internet.
You could use the 1522 mesh aps. You can run them in bridge mode, which effectively makes the mesh network a big switch.
In terms of encryption, you'd have to do something else. The lwapp/capwap aps don't encrypt client traffic on the wireless backhaul (5GHz), only lwapp/capwap control traffic. If you're talking about encrypting traffic from the client to the AP (2.4GHz), yes they can do wpa/wpa2.
As for no line of site, you might need a relay of some sort. Another mesh AP would work for this. All it would need is power.