My advice is to put a PC in the loop and let it act as the "Crestron control unit". That is exactly how the theater and general audio in my home runs.

The one caveat is that you need to be a fairly competent programmer. It is easier to program a PC to do IR and RS232 than the Pronto PRO. It is fairly straight forward to have the PRO send and receive TCPIP commands and replies from a PC running a dedicated server application built to do just that.

In fact my entire house runs that way. The only user interface I use these days are the Prontos', one in each room and talking to Dedicated PC's for specific functions (Music via Squeezecenter, Home Automation via Homeseer, and The Theater and Audio system via My dedicated Home Theater Control Application).

Much much cheaper in physical device costs than a Crestron, and Prgramming is a hobby for me, so I do not count the labor cost.