Router - ballscrew on one end

I am considering buildings a router with geometry similar to
<http://www.rainnea.com/cnc_5axis.htm> where the x and y axis are on
the top of the machine. I have ballscrews and large (2.5") round
linear ways/bearings to use on the x/y axis. The y axis will have 48"
travel. The machine frame will be steel.

My question is can I drive the X axis from one side of the gantry or
will it bind? I only have 3 ballscrews.

Roger