CAM without CAD? how can I do a copy/reduction lathe?

Hi to all,
My CAD/CAM expertise is pretty shallow, so I'm hoping to benefit from
the group's combined knowledge and experience. I want to model
railroad in an oddball scale (why? - personal demons). I'd like to
build a dedicated CAM mini-lathe to make scale reductions using as
templates larger scale model railroad wheels (no wheels,no model
railroading). Also steam/sand domes, ornate finials, etc. Since I
already have the larger scale parts to use as templates, I'd like to
avoid the CAD drawing step, and just go straight to a slaved reduction
lathe. I'd like to use inexpensive digital readout scales w/SPC output
mounted to an X-Y template follower to input D and X inputs to a CAM
mini-lathe system. Can anyone advise me how this package might be done
relatively inexpensively? Are there inexpensive CAM programs that
would take SPC data as input? That could do the scale reductions and
drive the CAM mini-lathe? Would I need to go through a PC? through MS
Excel? Anybody ever see anything like this?

Thanks for any help.
Karl Wally
Lafayette, California