I don't know if there is a market for it.  But you could represent several CNC machine companys and carge a commition on each machine sold or brought to the CNC seller.  The new sellers of machines have all there Programing things sorted out to make the sales go though better (I have see that).  They will send out a tech person to work out the bugs.

I have also seen shops buy old (used) CNC equipment and have real progaming problems to get those machines to run properly.
The people running the machines need the education to run it.  That could be a market.   Used equipment post processers need alot of tweeking to run error free and are sometimes unsupported by the company that originaly sold the equipment.  

I have a drafting company. As an example I have an old Calcomp plotter.  Calcomp went under but the plotter is a good one and still works.  Software is getting better and the plotter won't accept the files sent to it.  Calcomp is no longer and won't make it work.  Now if someone wrote the right kind of software to make that old thing work right.  They just might stumble across a small mint.  The same is often true for CNC equipment makers.

Regards
Rick Marmei

Rick Marmei - Tool Designer
http://axis-design.org