Mark IV systems has a spec for OTTO. Mark IV makes automatic toll collection and related systems O(Not to mention other automotive products)
The system spec's show support for IPv6 and SNMPv3. Notably absent was IPv4 as far as I could tell. No notes on if the IPv6 would be used for Firmware updates or live data collection. 802.1p radio is the spec'd LLP. O/S is VxWorks.
The expectation is for 100% of new cars to have OTTO around 2010.
Topicality: Looks like someone, somewhere intends to be live with IPv6 in 3-5 years.
Off Topic: The privacy and security ramifications boggle the mind....