It's not actually the weight that matters, it's the fact that the flight manual says "minimum crew two pilots". The FAA can only give you an exemption from that within their own airspace.
The CJ (525) series and the VLJ's are single pilot aeroplanes so no problem arises for private ops, however JAR-OPS 1 says that all jets have to be two crew for commercial ops. This makes it unlikely that air taxi will be very viable with the VLJ's in Europe.
Also, there were a few SP Citation I's and II's, designated 501 & 551. These had various differences from the standard aircraft; trivial ones for the I but quite major (the MTOW) for the II. If you get hold of one of these they can be quite legally flown SP in Europe.