HDMI switch
Herby,
I am not aware of any HDMI switches that also have optical audio. Also, new models are speced to HDMI 1.3 but 120 Hz is not standard. Are you aware that the HDMI cable caries the Video AND the Audio signal?
There are plenty of 4 input switches on the market. Monoprice sells a cheap one that might work for your application. Oppo, Impact acoustics, DVI gear and others offer higher quality versions for about $100.