Geoff,
Unless I'm mistaken, the Sport and PS style tanks are the same, but for the fairing mount bosses. Is this accurate? If so, we would only need two tools made. One for the S1K and PS style and the other for the GT style. I believe the S1K can be adapted for the PS style by adding brackets, which could be provided along with the tank as a complete kit, similar to the Air-Tech race-only kit.
We can get the scanning and CAD work done here. Basically it comes down to taking the raw data files, making a conforming 3D image, massaging it for symmetry and then looking for problem areas the tooling can't produce efficiently and modifying them accordingly. After the tool geometry is finalized, we can add the filler, vent and fuel pump bosses, as well as any mounting bosses required, either as weldments or as features of the base pan.
As I've said previously, the tooling is the tough part and therefore the most expensive part. The cost of the tools determines much of the per unit cost, based on the quantity of parts we run. A $10,000 tool adds $20 per tank to a run of 500 units, but $200 per tank for 50 units. I suggest we bring this project to the stage of tooling cost quote for the S1K/PS tank and then see what the cost vs. level of interest ratio is. If we get a good response, we can then attack the GT tank. This will save both time and money during the pre-production phase.
The ballpark quote I gave you was based on a run of 500 units of one type (meaning off 1 tool), unwelded. Welded, pressure tested and completed units would obviously cost more. As an option, we could also produce them in brushed or polished finishes at extra cost. All these prices are quantity sensitive, so the more we make in the first run, the less expensive each unit is...so this is one case where "The More The Merrier" really applies.
Although I expect to get considerable feedback from interested members about the features and design of the tanks, please bear in mind that it may not be possible to incorporate ALL of your great ideas in a production unit. Please don't be insulted if your idea is not usable in production. This is particularly true in terms of the shape of the shell itself. Other features may be possible to add as options.
Just for hahas, I'm going to get my seat cowl and front fender run through the scanner too.