@bflance: I have xrdp running on several server platforms, including CentOS 6.4. Granted, in my case, I had to manually compile and install XRDP, but it worked after a bit of debugging. In our particular case, I use vnc4server as the backend layer, along with the 'libvnc.so' library, and a series of rules that I've created in "/etc/hosts.allow" & "/etc/hosts.deny" to block direct VNC connections. In each instance I've built out, I use XRDP's customizable menu to build a resolution selector, with each resolution associated with a particular VNC port number (example: 5900 = 1024x768; 5901 = 1280x1024; 5902 = 1440x900; 5903 = x11vnc-console session with password protection).
I also combine this configuration with "crypt_level=high" to force all connection-negotiations to use 128bit encryption, end-to-end.
The VNC service configuration is a bit tricky per platform, as each platform tends to have it's own nuances in regard to what it supports. But, in my configuration, I use xinetd for auto-spawning the VNC backend sessions, and within the xinetd.d scripts that I built for this purpose, I also have each instance set so that the client connection will receive the name of the system they've connected to as part of their titlebar text, which makes it really easy to keep track of what system you are connected into when you have several sessions open at once.
I built this out as an RDP gateway from the start, and then even took that farther to integrate "guacamole", the Tomcat/RDP client that runs from a web browser.
While I've ran into a few challenges where XRDP is concerned, I've overcome each of those challenges through extensive research, development, and debugging.