CT-MI and NY-WI will definitely split the next time the GOP breaks 300 EV.
OH-TN requires a close election or Fred as the GOP candidate to split in 2008, and I'm not at all convinced that 2008 will be close, even if my current prediction is a close election with OH and TN splitting. However, my prediction assumes a third party candidate getting 5% of the PV. In a D-R only contest, I'd have Tennessee as a Democrat tossup right now.
You much be joking if you think TN is a Dem tossup. At most the Dem will get 46-47%. Middle TN and Nashville suburbs have gone sharply to the right, and ETN is already blood red anyway. There are still some Dem strongholds in WTN like Memphis, Haywood Co., and the counties that border the TN river and MS river (minus Tipton), but that's about it. Therefore, I declare TN is a red state in '08 and probably in '12.