Here comes the Skype fix! This also solves using microphone and speaker parallelly. The fix is actually using the stock libaudio from Galaxy Tab 10.1 and adding the necessary modifications to libmedia and libaudioflinger. Voice calls work fine.
Note: These libs have the Samsung audio bug! Sometimes volume settings are a bit weird, even though I have enabled the patch. Be aware of this.
Link: http://www.mediafire.com/?49u6ua55kbr1j6b
Thanks Adam, gonna try this out!