Hey Festdewalkita,
I think anybody should have the right (or the claim) to use the entire workspace of a CNC machine you buy (I have this claim). Especially when you have a gantry-style machine that allows tiling of larger workpieces due to the front and rear being completely open. But you have to think of swiveling toolsetters and tool changers with swivel arms then 
(or an entire tool magazine that slides out of the way)
Regarding homing X & Y, my opinion is that going the proximity sensor way solves the problem but you can still have a fence to position your tiling workpiece without zeroing X & Y.