The American philosopher Homer Simpson once praised the concept of the motorhome as "a car I can go to the bathroom in." The custom-built (no, sadly, this was not a production vehicle) Bath Tub Buggy made by George Barris during the 60s and 70s is the fulfillment of this dream:
The design features a bathroom. In front of the grille is an actual handsink. The rear displays a french bathtub. Hardware and facets for each bathroom fixture is included in brass. There is a tile flooring with long hair mats. Front headlights are spot beam or flood and the rear lights are ornamental styled bathroom fixtures.
The listing doesn't say firmly that the fixtures aren't also functional. There's really one one way to know for sure.
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=260789351608&viewitem=&sspagename=STRK%3AMEWAX%3AIT#v4-38 via Jalopnik | Photo: eBay