I just got the Nexus as well! Loving every bit of it.
I have not tried an iPad - I am curious if this works as well.
I asked in another thread awhile ago about getting Android running on it; didn't have much luck. I was thinking building a small box to house the components and output the display to the A/V in, but then the touchscreen wouldn't work... etc. Then I thought about just outputting via my old Droid, but it didn't have video-out. The Nexus does though, so when I have time I'll look into that.
I am not aware of any firmware updates - there is nothing under the downloads section of Pioneer's site in the 4300 section.