Simultaneous audio output?

No i don't think so. All player shutdown the Analog video circuit when in HDMI or the reverse, if they are in Analog , they shutdown the Digital Video Circuit..

I suspect there is a single digital audio output sub-system in most players, meaning only a single digital audio output is created to feed the D/As, Optical and HDMI Outputs? So if the optical output is 2.0 PCM, then the HDMI output would also have to be 2.0 PCM? If the HDMI output was 5.1 PCM, then there would be no way of simultaneously supporting an optical or analogue output without doubling up hardware?

This could cause confusion - so the easiest solution is a single output. It is annoying - as I would like HDMI 2.0 audio permanently feeding my TV, but a 5.1 Dolby Digital feed to permanently feed my amp, so that I didn't have to reconfigure my PS3 every time I listened to a BluRay. (I'm happy playing the odd game and watching some video playback in 2.0 via my TV for non-critical audio stuff)

The analogue output is derived from a digital output - something has to create a 2.0 analogue feed from somewhere.

FYI: Recent duplicate thread here... http://www.avsforum.com/avs-vb/showthread.php?t=909719