By the way, I assume you're all aware of those CNC routers that will
mechanically remove copper from a board, given a pattern.  They sell for
as little as $10k-$15k new (I think "ready to use".)  They may be available
used or refurbished at a considerable discount (I think a salescritter once
told me $3-5K.)  Not exactly pocket change, but perhaps something more in
reach of a small company or school than you expected.

BillW