Last couple of months I've been working away on my machine as have many others. I went for welded steel mainly because it sounded fun and would deliver an interesting learning experience (had not welded before, and is the first metalwork project since high school). When coming to a new joint or idea I made tests to make sure it was going to be right before moving on. Some of the lessons along the way are: "you can always grind it off and try again", and "don't weld over a pile of dry leaves".
The design is all original with a few running ideas... each axis has a main track and the other is sprung with high tension (to allow minor inaccuracies and misalignments... and it seems to work really well), the steel rails are tapped and faced with aluminium to make a smooth track that can be replaced in time. Everything can be dismantled with wing nuts, and the rail nearest the camera can also unbolt and swing down for access to the table. There are a couple of flaws (mainly the truck positions on the gantry with respect to the router), but it should do what I want to do (mill foam and wood).
The computer and controller boards are all made up (hobbyCNC) and ready to do. So what's left to do is mount the router and the motors with motion control (my control will be worm gears and "belts", which will make it all seem even more freaky). A bit to go, but it's certainly getting there.
With any luck I can take out the "most steampunk", "creepiest setting for a cnc" and "best CNC made primarily on a garden tractor as a table" awards.
...my welds are certainly getting better though!