Sadly, the Wi-Fi Caravan didn’t quite pan out like expected:
“The first mistake I made was underestimating the problem of powering computer equipment in a vehicle. … It was quickly discovered that under the load of nexus, the main wireless server, the inverted would just barely support the load. If we tried to power an access point or laptop in tandem, the voltage to the inverter would drop below the nominal 10.5V and it would then silently power off, requiring a reset.”
Read all about it at c o d e r l o g (as of July 2003, this link is broken, sorry).