I think the idea for a structured guide to cnc machine building is a excellent idea, Jonathan's parametric CAD design could be the ultimate goal of such a guide, but first of all much of the data would need to be gathered in a structured form as Lee is suggesting. It would be an amazing resource and would have saved me many hours of drawing and creating a Bill of Materials on a machine I will probably never build - RE: BuildingAfloat I have published the current layout in my thread, while it is not complete yet, it is pretty much the machine I plan to build (if there are no glaring errors!).
When my machine design is finalised, I am going to see if I can make it "parametric" so all one needs to do is enter the desired cutting area and the frame and components should scale from there. The calcs aren't difficult and I'll do a BOM in Excel that wil be parametric, just not sure if Sketchup has that facility yet.

It is clear that there are many many designs from "hose clips and skate bearing" builds through to totally dedicated machines and a massive spectrum in between. Maybe a critique of the various components that are commonly available to the DIY market, together with an axis by axis analysis of the various layouts possible could be collated from the vast knowledge base we have here. All spreadsheets we have stored in one location would be useful - I have a pulley and belt spreadsheet I will tidy up and post, if there isn't one already? - I couldn't find one easily and that is some of the trouble with an "organically" grown space such as this.

I agree totally, one design will never fit all, but we can provide the pros & cons of particular layouts, components or even complete machines as a guide for those who are brand new to the subject or even just to help those that are having problems visualising what is being said.

I strongly beleive having a machine layout (or layouts) that MYCNC recommends as a starting point, would in no way restrict innovation, but it could save those of us that are not design genii a lot of time and aggrevation.

Cheers,
Geoff.