I don't even think they would need to do it in house - if they can offer all of the on-line services that Google offers - gmail, maps, an app store etc, then Android vendors could use that as a way of distinguishing their offering from that of other Android vendors. I'm thinking of Nokia specifically - it would give them something that a plain-vanilla Android wouldn't have, and it would give them the freedom to get out from under Google's thumb, and really allow them to innovate.