One viable option is start a B2B job shop:
- Lease several rapid prototyping machines. Hire them out at 800% markup on materials (instead of the customary 1000%), thus undercutting the next lowest bidder by 20%.
- Lease a waterjet to cut sheet metal. Do short run projects. Sell own projects on side during downtime.
- Purchase a laser cutter to cut sheet plastics and papers. Cut custom stencils or signs or wedding invitations, etc, at reasonable prices. Make money on the volume. Also use for side projects.