Joshua I agree with Comanche, if your bike is a carbed bike then there is probably a way to fab it on. You might have to maybe add some glass mat and bondo if the styling don't suit you, and then paint it up.
When I was much younger (and much dummer) I bought a Fiberglass Chopper (Sportster style) tank for my Bobbed out Triump 650. It came with inset aluminum threads already in the Fiberglass tank.
I bought and installed a brass pipe adaptor fitting that would accomodate my Trumpet petcock threads to the new tanks threads. Then I rode to a welding shop with the Fiberglass tank between my legs with a heavy towel between the new tank to be and the Trumpet tank.
I showed the welder what tank I had and where the mounting bolts where, and asked him could he do what I needed. He said yes, so in his parking lot I removed my OEM Trumpet tank and rolled the bike into his shop. He welded me a couple of plates on each side of the backbone, set the tank on them, marked and drilled the holes.
I then mounted the New Bobbed style tank onto the my bike, put the heavy towel on it and rode home with my OEM tank between my legs.
As I said I was much dummer back then. But your tank probably can be modified to your bike.