In the past, I never found any RDP server available for a Unix-like system whether it was Mac OS X, GNU/Linux, FreeBSD, or whathaveyou...
...And then I found this:
I'll be giving this a try really soon as RDP seems like a better option than VNC in terms of speed. The only thing is that RDP (at least in Windows) is very insecure. I guess at leat in the Unix side it can be tunneled through SSH just like VNC can if need be. The only bad thing is that it might only apply to X Window sessions.