Holleyweb offers tents, which can sleep one as in a bubble. That, however, to the $1000 stump up. Nicht gerade günstig, aber ich würde ja schon gerne mal drin pennen. At the beach…

Inflatable bubble house can be easily installed in parties, parks, amusement centers, backyard, gardens. Cheap inflatable bubble lodge for outdoor camping and beach sight-seeing.

Sleeping in a bubble
Sleeping in a bubble
Sleeping in a bubble
(via Laughing Squid)