Sadly, it is not legal to import plants from Germany without a lot of expense and risk. I don't recall exactly how it can be done, but it involves getting an import license, a certificate and I believe, a quarantine period for the plants involved. Some still attempt to do this illegally, but the risk of doing so is very high, involves severe fines and even possible jail time.
You can find more information at this official site:
http://www.aphis.usda.gov/impo...
Having said that, it would be nice if some of his plants could be legally imported to the US. I believe from time to time that some of the larger sempervivum sellers do occasionally go to the expense. We need a couple "millionaire" members!