It sounds like you want an HDMI switch with optical audio and 5.1 analog out? I have only seen them with 2.0 analog audio out.
You might need to use a separate HDMI switcher with digital audio out and an 5.1 decoder.
http://www.monoprice.com/Product?p_id=5557&kpid=105557&gclid=CPPY2sLnwcYCFYIXHwodhY0FTw
http://www.amazon.com/Panlong-Audio-Digital-Decoder-Converter/dp/B00AMC2J1Y
Most surround receivers don't have preamp outputs so if you go for one make sure that it has them.