About 10 years ago I came across a Toyota jeep with European license plates parked by Bowman Lake in the Sierras. It was obviously a world-traveling vehicle. On top of the jeep�s roof was a tent. I could see the owner down swimming in the lake. Fascinated by this approach to sleeping while on the road, I wrote down the name of the manufacturer: Air Camping in Milano, Italy. Some months later I tracked down the company and ordered one. It was expensive, about $2000 including airfreight, but the expense turned out to be worthwhile.

The unit folds up and can be mounted on a truck or car top. Closed it measures about 4 x 4 feet, and about 14" deep. When you stop for the night, you remove the waterproof cover and unfold it -- whereupon the tent pops up. The cantilevered section is supported by a telescoping ladder. There's a mattress inside, as well as blankets and pillow, so your bed is ready as soon as it's set up. I've spent 100s of nights in it, usually in the desert or on Baja beaches with the opening facing the ocean. Its got mosquito netting, is well made and it's great to be up there for the view and breeze. It�s comfortable, and the tent does not take up storage space in bed of the vehicle. I don't believe Air Camping is still in business, but a German company, Autocamp, makes what appears to be a similar product.
�Llyod Kahn

Autocamp-Kn�ller (in German)
130x220 cm, for 1-2 people incl. mattress,
mosquito net, covering tarpaulin, cotton
$600-900

Also, here are similar models from North American and UK manufacturers, but none we�ve tried out yet:
Lofty Shelters (US)
Top Bunk (US)
Outdoor Equipment (Canada)