I can't comment on growing the pumpkins, or anything about how to obtain the seed. But I lived in SE Austria (Graz) for a year and had the Kürbiskernöl (kuerbiskernoel) aka pumpkin seed oil, numerous times. Every time we return to Graz, I pick up a tin of the oil to bring back to the states. The Trader Joe's variety pales in comparison.
Styria (the state in Austria) is the only region of the world where the product comes from (though all pumpkins originated in the America's), and they protect their seeds and crops pretty closely because of it. It's a culinary delight, and much sought by chefs. Just like any food product, wine, etc, they have awards and gold medals yearly. There are good seed oils, and cheaper & less tasty ones from the same seeds. It all depends on how it's grown and how it's processed (like any foods).
The oil is volatile, meaning it can't be heated without destroying the taste and qualities. It's a perfect salad oil but they also drizzle it in hot dishes (pumpkin soup, for example), as a marinade, and various other applications. They also use the seeds for snacking - coating them with vanilla, orange and chocolate flavors (to name a few). They use the seeds in breading for wiener schnitzel as well.
The oil is dark green and stains clothing easily, but if clothing is left in sunlight, the green disappears. You still have to deal with the oil removal, but at least the color is easily addressed. I don't know if the pumpkin is edible. Based on what others have said in this forum, it appears it's not. I'm really not sure about that, because we had pumpkin soup (orange in color) with the drizzled green oil and cream. I always assumed it was from the same variety of pumpkin.
Here is what the main website says about the control of these seeds and products:
"With its designation as a product of Protected Designation of Origin, Styrian Pumpkin Seed Oil P.G.I. joins the company of products such as: Champagne, Prosciutto di Parma, Prosciutto di San Daniele, Greek Feta Cheese and Nürnberger Lebkuchen as one of the most well controlled, elite and exclusive European specialities."
Here is the full article on the topic of origin protection:
http://www.steirisches-kuerbiskernoel.eu/index.php?option=com_content&view=article&id=46&Itemid=93&lang=en
Here is the rest of the website:
http://www.steirisches-kuerbiskernoel.eu/index.php?lang=en
The pumpkins are orange with green stripes, yellow/white flesh, and green seeds. They are hull-less. They are Cucurbita pepo var. styriaca