Here's what I want to do:

I have one input which is stereo RCA audio (Wii audio output) and another input which is also stereo RCA audio (digital media streamer output). What I would like to do is find some kind of mixer/combiner that would allow me to take both of these inputs and combine them into one stereo audio output. Ideally this mixer/combiner should have some kind of line-level control so that I can adjust the volume balance between the two sources. Even better would be if the mixer/combiner had remote control functionality such as: "Select only input1 as output", "Select only input2 as output", "Mix/combine input1 and input2 as output", and "Adjust input1/input2 volume levels".

I just can't seem to find anything that isn't totally overkill for what I'm looking to do. Even if someone knows of a simple passive decide to combine two stereo RCA audio inputs that would be excellent, but the ability to control this remotely from my Logitech Harmony remote would be the ultimate. Maybe I'm just not using the right search parameters? Thanks in advance for any help you can provide.