Certainly to build one the theory behind it wouldn't be tough, it'd operate on the same principles as the stove setup. To buy though? There's a story of a boy scout who did something similar as part of a personal experiment in the 90's. (Before getting raided out of fear by the FBI) Will have to find that story again.

In almost every country the materials required are tightly regulated and getting permission even in a lab environment is tough work. If you can work out the legalities and safety, I'd be interested too!