I have seen discussions and plans for a Farmbot that is based of a circle design instead of a square CNC design. http://wiki.farmbot.org/media/farmbots/orbicular_farmbot_1.pdf This would really allow for further square footage expansion without compromising as much structural integrity. The problem that i see with this design is square footage efficiency when downsizing. The current model is great for maximizing smaller gardening plots.
If you wanted to stick to the CNC format, I’d imagine a turntable or transfer table design, similar to what you’d find for locomotives in a railyard, would efficiently transfer the Farmbot from one plot to another. If you had a barcode on each plot, the Farmbot could recognize each plot and differentiate plot from plot. You’d also need the ability for the Farmbot to quick connect to a new water and power source with each new plot. You could mount the vacuum on the Farmbot to minimize the number of fixed supply sources.
Another brilliant suggestion that I’ve seen is mobile planting beds. The Newbs guide to Farmbots limiting factors and strengths The Farmbot stays fixed, but the planting area moves. This could have significant applications in hydroponics!
I can’t wait to see what these expansions look like, once brought to life!