I know this has been asked before an the short answer was "no", but the latest post I could find was able to find was dated mid '07. Five years later, Im hoping things have changed and someone may be able to suggest a head unit that is able to accomplish this :

I am a huge tech guy, and want to add a carPC to my newly bought 2011 Sonata. I will be swapping out the head unit, and I was hoping that advancements in technology have been made to the point where head units (or at least a specialty head unit) is sold commercially with an input for a CarPC WITH the touchscreen working (or some type of relay/overlay/video controller I can connect between the CarPC and the aux input on the head unit).

The CarPC is an artigo a1150 running Win7 x64 with 4GB Ram and a 40GB SSD (and a 320GB external drive connected via USB). It has HDMI support, if that's also relevant.

Thanks for reading guys, I appreciate any help.