I know that it would be easy enough to do this with the x3, provided you were able to get a longer leadscreaw for the z axis. It is built inside the column and would need to be extended as far as the addition.
The X3 table is pretty basic as far as mounting etc, and I could see where a replacement table could be fabricated and add quite a bit of space to the overall work envelope. I am comfortable with the travel I have now, but that may change someday.
With all the information about casting, etc on this site. There is hope for us all.