So.. I think everyone here has come to the same conclusion: there will never be another N900!

So to get more life out of the device, I think it could be worth doing if:
1. TI, confirms the newer TI chip would work with S/W updates (lower power etc).
2. If yes, see who's interested.
3. Then find someone with the equipment and skill to do it.
4. source the newer chips
5. Pool in some money for a second hand or refurbished N900 as a test.
6. if test worked, Pay and send it away

I'm not sure how much it would cost, I'm sure it would be under $200USD??

As time gets on, this question will become more important!