AgX, yes I didn't want to put people off with a huge wall of text on my first post so I limited to an introduction. I hope that people will be able to do more than just look over my shoulder, feedback from the people who may be using the final product is very important to having this work out IMO.
The design is slightly more advanced that nothing, I have significant detail design done in CAD and have ordered some prototype components, however it's still early days. It will probably take a few blog posts to fully get up to speed with where the design is now as I think it's important to explain how I got there and the choices I made along the way.