If anyone is interested in the idea of a folding double bass which isn't a gimmick and looks the part (because it IS a standard double bass!) then check this out:
[url="http://foldingbass.com/"]http://foldingbass.com/[/url]
I was lucky enough to tour Germany last December alongside an American bluegrass band whose bass player had one of these instruments. He has a 'nicer' bass at home but since owning the folding bass said he uses it more and more on the road and leaves the other one at home.
After the neck broke away from the body of my own bass due to extremes in temperature and a weak neck seam, I was fortunate enough to be able to borrow his bass for the last two gigs of the tour. It was very comfortable, easy to play, had a big, woody sound and looked gorgeous.
From the front you'd never tell it was anything but a normal double bass. The only thing that gives it away is the removable panel on the back of the body which cleverly enables you to store the bridge, end-pin, tailpiece, removable fingerboard and the hinged neck.
The bass is sold with a tough hard-case as standard.
It's a very clever idea.