Re: 3D printed in-frame plastic gas tanks
James will make anything you want. He is a skilled guy,and can work with a simple pattern to make what you want.
Additive machining is generally a rapid prototyping medium. Skipping a lot of steps to get a single prototype out is a hurry is worth big bucks to companies like Lockheed - and they pay for it.
And that fork? well, yeah. I have seen worse, but that one is pretty bad. At lest the tank will stay together when the fork fails.