We never investigated this, really, due to lack of time, but what chances are that the NoMachine server for Linux can work using the Linux compatibility layer?
If most binaries work (as I expect) adding FreeBSD support as if it was just another Linux distribution would be at easily feasible. This would at least open NoMachine to the fine BSD crowd. I wouldn’t mind performance. The underlaying NX software is very POSIX standard and, as you certainly know, Linux executables work on top of this BSD compatibility at their full speed.