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?
http://www.freebsd.org/doc/handbook/linuxemu.html
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.