I haven't built one but I suggest you pick up a local HUB (magazine) and copy the specs on an MCE machine?

Here's an example from a computer store in YVR: http://www.atic.ca/index.php?page=LongDesc&sku=13461

As for transmitting to other rooms, I seem to remember Future Shop sold some wireless transmitters years ago for about $100. I have no idea if they still sell them.