You should be able to do this, by configuring the Wifi on your laptop into a hotspot. Your laptop should then appear as an access point that your iPad can connect to, as if you were using a Wifi access point.
Details on creating a hotspot are here:
http://lifehacker.com/5369381/turn-y...reless-hotspot
And then its just a matter of connecting the iPad to the hotspot and running the DisplayLink app.
Wim