There is almost too much information available for a beginner to know where to start and I simpathise greatly. If you look at other forums and blogs from CNC users you find people cutting wood using machines that would be laughed out of town by MYCNC forum members. Angle iron (or even aluminium) and skate bearings for rails, plywood frames for base and gantry, Makita routers as spindles and so on. If you want to make carved signs, bass relief maps of New Zealand to hang on the wall or other decorative pieces they will work well enough, but my own experience tells me that if you want to cut out pieces of wood that will fit closely together, which I believe is your aim, then you need the kind of machine described on this forum.

Whether that commercial machine is capable of such accuracy I have no idea but some demonstration from the manufacturer before you purchase it would be advisable. You should also confirm that the spindle can cope with the kind of cuts you want to make. I'd want to see an example machine cut out some pieces to my design before parting with that much cash. One of the things you'd expect to be paying for by buying a commercial product is a guaranteed level of performance.

I like the idea of a MYCNC reference design, and there are several close approaches to be found here, but there would need to be at least half a dozen variants to suit different budgets and requirements. The steel v aluminium choice will be different for different people and a wood-only machine can be a little less robust than a machine for cutting aluminium, though the dimensional accuracy still needs to be very good. Probably one of the trickiest parts of the design is deciding how you are going to do the final alignment of the machine and how to design it to make that as easy as possible. You need to keep this in mind from the start and a good reference design would include how to align it for best possible performance from the materials chosen.

Sorry, that turned into a bit of a brain-dump but what else are we going to do stuck indoors every evening? Maybe that should be a topic of it's own!