There are actually 2 versions: the Red-Dot-awarded "Z-watch" with rectangular case and interesting clasp mechanism (click here), and the one you probably purchased, with a normal leather strap and clasp and a somewhat rounded case (see here).
Someone tol me the Z-watch was given as a X-Mas present to BMW employees in 2004, ebay was flooded with them (they sold for 300-400EUR).
Here's an old thread about the Ventura/BMW: http://digital.superman.ws/phpBB2/viewtopic.php?t=523