I've just read through the last two pages or so and I'm amazed by the work that's going on, so congratulations on that! All in your spare time as well!
My only thought would be.. So far there is two(?) more famous bassists in the line to sign it etc. but what happens if after these people another famous person says 'Oh yeah, I'll do that' and then the bass is held for longer and on and on..
But!
Please do not take this as a criticism, just a honest question?