ballscrews

i have a larger desktop mill that i want to convert too cnc also.
is it possible to mount the ballnuts on the saddle in the far end of
screw travel on the saddle? in order to keep from drilling too many
holes in the saddle and keeping the mill as "stock" as possible. in
case i decide to sell it down the road as it was when purchased.
i was also thinking of doing it this way in order to eliminate the
need for a bearing opposite the motor/handle end of the screw, and
have only angular contact bearings on the screw, at the motor/handle
end. would this work??
the ballscrews are a decent size (5/8th dia. double row, 22" Lng)
rated for more than i anticipate on putting to them.

anyone see anyproblems with these ideas??

thanks all