Ray, thanks for the vote of confidence ! Custom built tanks are worth all of the $1000 or so to do one. If I were making a tank I would be sure to install the baffling foam inside to reduce fire hazards. I have done CAD (cardboard aided designs) designs of some weird tanks for gas and radiator tanks and bent them up for welding but I leave the aluminum welding up to someone who does it all the time for a living.
The Frunk hinges are pretty easy. Dlear already has a mockup. Even though it doesn't open far enough he should be able to make a satisfactory pair out of aluminum like Al says with cool looking lightening holes to boot. I would polish them too ! Always got to have a little "sparkle" !!
The only mod I did to the hinges was on the rear deck lid. I hated holding up the lid to find and insert that little pin. With this one, it locks in place when you raise the lid. Here's a photo for reference........Bruce