Tom Keating wrote a review of Panasonic's Android IP phone, model KX-UT670. It has HD Voice, speaker phone and integration with IP cameras. Tom reminds me that it's the "major IP phone vendors like Aastra, Cisco, Polycom, ShoreTel, snom, and others all use their own proprietary, relatively closed operating systems," while NEC and Panasonic are rolling out unique phones.
NEC has the Android phone that CloudTC showcased a couple of years ago. NEC also has a tablet docking station that allows your tablet to become a phone! (One of my pals said that unless it locks that tablet will disappear when the owner gets a cup of coffee.) NEC has a significant problem on the web though. No Google juice at all. I could not find anything about these 2 phones. I could barely find a website for NEC IP Phones (which they term IP terminals, the SIP terminals are just Polycom).
Of course, Grandstream has Android phones too. The Grandstream GXP2200 even features Skype, Google Voice, Microsoft LYNC as well as Android 2.3.
I often ask why the 1000+ VoiP Providers don't take advantage of the IP Phone. It is a computer that sits at the user's desk all day, capable of a bunch of nifty programming. That would be a great way to differentiator yourself. It is going to be Integration that separates the commodity from the premium.