Here's the problem.... For the WiFi-only iPad to communicate with Skyhook's database, the iPad has to have an internet connection. So, no, you won't get a Lat/Lon if you aren't on a network.
It's TWO parts that are needed for WiFi triangulation... 1) A "mapped" WiFi hotspot (a WiFi base station with a MAC address that is known to Skyhook), and, 2) A way for that information to be shared back and forth between the iPad and Skyhook.
Without an active WiFi connection, you can't achieve number 2.
Mark