Hilly,
The 2008 FatBob I test rode in Mackay is exactly the same as the 2010 FatBob that I brought which is exactly the same as the 2011 FatBob that was in the showroom when I picked up my bike. Other than paint choices that is. But there maybe some small differences tho.
I will try and find a tape and get that measurement for you tonight.
Hilly I just ran the tape roughly from the centre of the fork cap to fork cap and its pretty close to 10inches metric on my tape says 25.3 ( I dont know metric)
Just with a tape measure i got 250mm. Which is pretty close to Daggs.