I’m in that same boat. Moving to Okinawa. I talked with a local machine shop for a quote to do a XL (looking to upgrade from the standard as well) and for material and machining holes 1" apart with every other hole threaded (can’t remeber how many holes it totaled up to), it was going to be roughly $500 or so. I’ve done business with these guys in the past and was getting the material at cost. I’d talk to some machine shops in your area and see what they quote you. I was wonder how the T-tracks would mount to the Shapeoko 3 aluminum bed that Carbide3D offers especially since they just had it on sale for Black Friday.
While you could probably mount the T-tracks on the aluminum table — why? Just thread directly into the holes.
If you want a metal bed and T-track, the way to go is either aluminum extrusion, or a cast bed which has the tracks machined in it — something like this:
Unfortunately, I haven’t found anything quite the right size to make an XL work out well.
This off-the-shelf extrusion was posted several months back: MisumiUSAExtrusion
This is available in a 250mm width and can be ordered at a desired length. The post had pics of an XXL with this full aluminum bed extrusion. The downside from the poster said that it wasn’t as rigid as he would have liked.
I could go investigate options from some local shops, but I believe there would strength in numbers. I’d want to acquire it before moving as well, so I’m hoping there’s something that comes from continued discussion. This is not the right thread for the discussion, however.
I personally love them and here is my review: