I do not know of any KVM switches that will also switch multiple audio channels. The main proferssional use for KVM switches is to control server farms.
I have been using a 4 port Cybex (now Avocent, I think) switch for years. I have not seen any noticable degradation up to 1600 x 1200.
I live by myself when I am working in Saudi Arabia. I have my network set up with Box 1 (gaming and multimedia) and Box 2 (workhorse) online through the wireless router. Box 3 (personal data) is offline. I use the 4th port for testing other computers. Laptop is tied to the router by Cat 5 cable. I have the wireless functions turned off - better security.
Since I have moved most of my games to the new box, I do not need to switch audio. But if I had to, I would wire up a little manual, multi-channel switch box.
Two of J.S. Casteel's Geek Test questions (with apologies to Jeff Foxworthy):
1. If you have more computers than people in the house, you might be a geek.
2. If you have a home network and you live alone, ...