I wonder if you could get a Federal small-business grant or loan of an amount sufficient to have a larger production run manufactured (at lower cost per unit). Your business is unusual in that you don't need a storefront, kitchen, loading dock, truck, oven, etc., so the usual expenses of starting and running a business are minimized. You probably wouldn't need any employees at this stage of the game either, meaning no wages or insurance costs. What I'm getting at is that you could invest nearly 100% of the monies granted or loaned to you into inventory. You'd have to do some serious math to determine the tipping point of the scale of operations, i.e. what quantity would you have to manufacture in order to get the cost per unit down to a level where the market would support you with purchases. If it was done with a grant then you'd obviously have some breathing room in terms of ROI timing, but if it was a loan you'd have to think about advertising and other competitive methods of moving the inventory in a timely fashion.
It boils down to this: at the scale you are producing them now, you are -as you said- priced out of the market, unless you are able to find 100 people willing/able to pay any price for your bridge. So that necessitates larger scale production. That takes investment money. Either you come up with the investment from somewhere, or you license the design to a manufacturer and accept whatever cut you can get from the deal.
There's a surprising amount of Federal money available for small businesses, although TBH a lot of it hinges on how many new jobs you are creating, which in your case is none (or very few).
I would ask around TB and your circle of friends to see if there is a business lawyer who would be willing to do some pro bono work to protect your design and personal interests while you shop the design to a larger manufacturer. It might seem like "selling out", but if you protect yourself with a tight contract this might be the best way to overcome your obstacles. If you stipulate that your name must be used in all promotional descriptions of the product, then even if Hipshot or whoever makes 95% of the profits, you will gain fame for your design, and that would almost certainly open doors for you to do custom work on the side and set your own rates for it.
Just thinking "out loud" here... stuff to mull over.
