When I was studying the table issue (on my standard SO3), I had figured it would be neat to:
(1) Remove the spoil board.
(2) Repurpose the mounting holes for the spoil board to run three pieces of t-track parallel to the x-axis. Use some spacers underneath these three pieces to make sure the top of the t-track is just a smidgen (that is machine-shop lingo right there) above the front and rear plates of the Shapeoko. This will require drilling/countersinking holes in the t-track to a fair degree of accuracy. Doable, but requires some thought. Maybe I wouldn't have to countersink, I guess it would depend on how the screws fit.
(3) Stuff each piece of t-slot track with at least a couple of nuts.
(4) Now run some additional t-track front to back of the machine (parallel to the y-axis). The bottoms of these pieces sit on the top of the t-track you ran on the x-axis. Drill each piece with three holes that correspond to the location of the X-axis t-slot pieces.
So what you would have is, t-slot that can be repositioned left to right. You just position it where you want it, then snug the screws. Then place your workpiece on top, and add some work-holding clamps.
Think of it as t-track tic-tac-toe, with three horizontal pieces instead of two., and the vertical pieces can slide and lock anywhere along the horizontal pieces.
The only thing that prevented me from doing this at the time was: (1) Didn't have any t-track available. (2) Concern over flatness and deflection. I have found my MDF spoil board to be flat to within +/- a few thousandths, I think I can adjust the t-slot even better. And I think for my smaller unit, I can provide some additional stiffness under the x-axis t-track if needed very easily.
Edit to add: (1) Now that I looked at my SO3 again, I remembered the tops of the lower (x) t-tracks would not be able to be flush with the SO3 front/rear. So I'd have to add washers between the x and y-axis tracks, which is how I planned on shipping things "just right." (2) On my SO3, the middle x cross-member could support two runs of track, and that is likely what I'd do for additional flexibility.