Yes it's possible.
I use a sitecom range extender which can also be configured as a wireless access point. It's a WL130 details
http://www.play.com/PC/PCs/4-/3123776/S ... oduct.html It's not a current model but I'm sure current versions would also work (as long as they're 12V like the W130).
I've plugged the ADL3 ethernet into the WL130, put ignition switched 12V into the power supply, extended the aerial to the top of the cage, configured it as an access point rather than a repeater, given it it's own SSID and WPA code. The laptop then see's it as an additional netwrok to connect to, the first time you connect you need to point it at the right SSID enter the WPA code and that's it, it just works.