Paul - thanks for sharing this beautiful model. I like your base. I have an "unmade" model kit of Karlstein published by Betexa in 2008. I am not sure that is the same model as yours as I see on the cover photo a few slight differences and you stated that you made your ten years ago. We had hoped to visit this castle on our visit to Prague last year but just didn't have time.
I am looking forward to building this model sometime in the future but have about 45 models yet to make of places that we have already visited with more coming up when to go to Southern France later this year. I am presently working on Carcassonne which is really a BIG model. If you haven't looked, please check out my web page -
www.cathedralquest.com and click on church models.