No doubt the Kaleidescape would do it for you, but at around $35K there are some alternatives.
The cheap way to do it would be to start with modulators. channelplus.com
You should take a look at mainlobby and DVD lobby to watch multiple streams of ripped DVD.
I'm thinking your going to need either multiple video cards in the server running the Main lobby server, or 1 PC for each DVD video stream that you need.
The channelplus modulators require no programming and run over your existing RG6 cable.
As of now, there really is no one "box" that you simply plug and play that will stream multiple instances of ripped DVD movies to multiple rooms that I know of under $25,000.