It's a truly impressive project, and I love the fact that someone actually built it. That said -- I'm much more glad it's not me trying to sell it. It's a very, very specialized airplane with one seat, four engines, and precisely one suitable mission (fly around slowly and look like a B-17). Your pool of potential buyers is vanishingly small. Personally, I can't imagine building something like that unless I personally wanted to fly the heck out of it... because I'd know the chances of selling it for any amount that wouldn't make me cry are very, very slim.