Hi,
can you post some more pics of the linear rails and the ballscews? Knowing the sizes, grades and even the manufacturers would be helpful. The basic machine looks to be very good quality
and if that is indeed the case it would make sense to try to match the quality if doing a CNC conversion. That would in turn give you a ballpark figure for the sort of hardware and electronics
you would want which determines what the cost would be. That's a very useful number to have BEFORE you start building it........it may mean you have to get a divorce before you start...(joking).

Craig