As I mentioned a while back, a line level switchbox was my upcoming
project, now completed. I normally wouldn't mention something so simple,
but I used an old idea to make a better unit for less money. I am using
3 4 pole double throw switches with all the switch outputs connected to
one pair of outlet RCAs. The net result is a box where you could have
up to three inputs connected to the output at one time -- the user has
to insure that only one switch is up or down. I bought the switches from
Michael Percy for about $11 each. These are on-off-on switches so there
is no connection when a switch is centered. I used 4P2T switches to
switch the grounds as well as the hots. Overly conservative in most
situations, but possibly a help in bad rfi situations. Good rotary
4 pole 6 position switches cost a bunch, and this gives equivalent
quality for half the cost or less.