It's not the Barrel Back of my dreams, but if the Tubby Tug turns out OK I (and my darling Wife) might be convinced that I can manage it!
Here's where I'm at:

I'm using Gaboon marine ply, which I was able to buy in over-size sheets (three point something metres long), eliminating the need for the side panel butt block joins. It's really nice to use! I started with MDF templates for all the panels with curves, then double-sided-taped them to the rough-cut ply before using a replicating bit in my router to match them. This worked great - gives a fantastic finish, and perfectly matched parts each side.
Anyway, am learning heaps and having a blast. Will no doubt have many silly questions to post throughout this process.
Cheers!
Dale.