I wouldn't buy into (literally) having the GPU process the audio. I can't see how they could manage sounds during intense battles of counter-strike, UT 2004, etc. Now that the more popular games seem to be using OGG or MP3 as their choice of audio compression, that seems like a decent hit on your GPU processing during needy game time. I see no problem during basic desktop use for things like DVD's, and basic audio...but games?
It would also annoy me if it came packaged on a graphics card. I don't know if we would see it any time soon, but PCI Express does open up some more opportunities. The on place I may make an exception for the audio being on a graphics card is for PVR. If they included Sound Storm 2 on a Hauppauge card, that would be a nice convenience. It would mean one less card to install in you SFF case. Hopefully they'd offer better integration of audio synchronizing to video, but I'm dreaming.
Having an 8x/16x connections for audio boards seems like overkill for anything short of real time audio processing of 32 channels. Back to the thread we had regarding SLI boards, I don't even know if you can use the second PCI-Express slot for anything other than a video card.