Anybody have personal experience with a Troles Graveson Subs?

After listening to JLs, RELs, and some really lousy el cheapos I'm tempted to build my own subs. Mostly because it would be fun to interact with a speaker in a micro level and learn a lot about them.  Then there is the cost:  It appears that you can build a Graveson 12" sub for about $950. So, is there anybody out there in Audiogon Land that has done this or heard them?  I'm really interested in what you have learned.