DIY?
I recently built a passive switch box for my friend 'bigfish.' It was single ended RCAs, not balanced, but it worked good. 2 inputs, one output. He uses it to switch between HT and stereo system. I built it in a few hours for a couple hundred bucks. He was worried that it would affect the sound, but he couldn't hear any effect.
I used a Goldpoint switch and some nice WBT Nextgen RCA jacks. We used a cheap metal box, but Par-Metal could laser cut the holes in a slick black anodized case.
The Goldpoint switches are among the best audio switches made anywhere, so no worry about signal degradation there. They have configurations for balanced switching. Use good Neutrik XLRs and some nice silver plated, pure copper, teflon insulated hookup wire. I don't think you will be able to hear any difference from the Ayre inputs. Goldpoint switch is open frame so it's easy to clean too.