related
There are a couple additional BMW cars that are related or derive their inspiration to the little Isetta. One is the BMW 600, sometimes called 'the big Isetta' or the 'Isetta 600' It retained the door as the front of the car but added one door to the side for access to the rear seat. The 600 derived its power from a 600cc motorcycle engine found in the rear of the car. The BMW 700 is considered by many to part of the Isetta line, but shares little of its traditional car-like design with the Isetta or the 600. It is powered by a 700cc motorcycle engine.

In addition to the Isetta, there were many other strange bubble cars to come out in the 1950s, some of which share a great deal of design influence from the isetta. Others are unique in their own right. I've also supplied a few links to these sites. And if any one has an extra mopetta lying around, please send it to me!
600

the aerocar 600
700

bmw 700 info site
some specs
a nice one in houston

 
other bubble cars

mopetta
i'd sing to birds every morning if i had a mopetta!
oliver's mopetta site is very nice. mail me a mopetta!
mopetta custom 
mopetta run!
mopetta literature
oliver's other site on the valmobile. carry your transportation!

messerschmidtt
the true blue: the messerschmidtt

vespa
vespa 400 (the car, yes, the car)

others
subaru 360
fiat 500
the new mini
microcar links
three-wheelers
a very cool bubble page
the gem car