My projects require approx. 31" workable carving distance along the Y-axis. Considering purchase of the X-Carve as a 2nd CNC machine for increased business. Currently have a 2’ X 3" CNC using Mach 3.
As long as you can get your hands on longer extrusions its absolutely possible. As far as the controller goes it doesnt care about overall size, its sole purpose is to count steps 
Inventables IIRC dont offer longer extrusions anymore.
Ugh. You need just an inch more than a stock 1000mm machine. I suggest contacting Inventables and see what they have to say. Might be a simpler solution.
Thanks for your help. One other question. How do I carve the models I already have in g-code with .tap file names?
You can load Gcode into Easel. Open Easel. Look under FILE. Import Gcode. You will have to ensure that it doesn’t contain characters that GRBL doesn’t like.