I still build frames for myself and a few select customers, primarily for all the reasons 41willys suggested. Liablility concerns. The insurance, if you can afford it, has ridiculous "attachments". My attorney read through the entire thing and interpreted it to read that yes, you have insurance but if something goes wrong and you get sued you're on your own.... Unfortunately, liability concerns will probably be the main reason a lot of small and big shops prefer to sell components only and not complete frames. I made it over the years by just sheer luck....nothing bad ever happened with one of the cars I built and I never had to go through the hassle of a lawsuit. A know of some shops that did, and it was ugly!!!!! No amount of waivers or disclaimers will limit your liability or release you from the liability. Not fair, just the way life is.

As for the frame itself, well, you asked. I have built similar frames and used the rectangular tubing in line with the front and rear kick ups, them built the perimeter portion of the frame out of either smaller rectangular or round tubing. On the rear suspension, I prefer a triangulated 4 bar setup with the bottom bars in line with the frame and the upper bars angled in then suspended with either coilovers or air bags. Some very fine worksmanship overall. Also, along with Nitro I would like to see some more substantial crossmembers, especially over the rear end housing. The crossmember in front of the rear suspension at the kickup is very substantial... If someone buys one and puts some 600 horse monster in it with a tranny brake, you don't want him complaining to you and other potential customers about frame flex.

There is profit in building these frames, but don't give away the freebies you can do at work... There is a cost incurred even if you are doing it on your own time using the shop's equipment. If the idea does catch on, I doubt the shop you work in will let you run a second shift producing parts for your frame... Always have enough built into the price to cover the incidentals like this.

As for the marketing, I would suggest installing a complete engine and transmission along with a complete brake system and start hitting the shows and handing out cards and pricing information. Remember too, that nothing on it is proprietary, and anyone who wants to copy it will do so.... If you can make an arrangement with a local body shop or builder, consider donating one of your frames to build a first rate show car and push the heck out of it to every car mag you can find the address for.