A sheet metal company here in Kidderminster has branched out into making a superb ground anchor for bikes. Their MD is a keen biker and knows the problems we face with thieves. Have not spoken to him for years but they used to do quite a bit of work for a company I used to work for.
A mate has bought one of these anchors for his VFR800 and really rates it. I have seen his bike in it and was impressed. Might get one myself when the wedge become available.
Anyway check it out on
http://www.saferack-sheetmetalservices.com
and make up your own minds.