So this story fortunately has a happy ending. It turns out that the basses (5) and bows (19) were stolen by a 26 year old bass enthusiast. He said that he saw the instruments and bows online, and came to want them. So when the dealer went on vacation, he came by, broke in, and helped himself! The stuff was all found safe and sound in his place in Atsugi, a town a bit outside of Tokyo. He was caught when he tried to break into another shop in Meguro to do the same thing....
That said, the whole thing might make a great ad for the mini-cooper. He took the 5 basses and 19 bows in 2 separate trips in the car shown at the end of the video below. The trip would be some 50km.
http://news.tbs.co.jp/jnn/asx/news4514644_12.asx
Anyway, just goes to show it's not a good idea to let people know when you'll be on vacation.
Brent