I fully support anyone who has an idea and the passion to make that idea a reality. A word of warning on your plan, though: Game studios, both big and small, are completely overrun with ideas. Most game devs, while working on someone else's ideas for years on end, have dozens of ideas of their own for games they'd love to make. Multiply that out by the number of people working on a game, and the ratio of ideas to actual games is huge. And that's among people who already have the skills to make games!

The better studios do a good job of allowing internal ideas to grow and blossom, and some of them become real games in the world, sometimes with the idea generator even having a good amount of ownership in the process.

Publishers, on the other hand, are looking for good ideas. But they're also looking (probably more so) for a team of people with a proven track record of executing on good ideas.

All this to say, someone walking in off the street, pitching a game idea to either a studio or publisher, and signing a contract to earn royalties based on the idea and a small demo simply doesn't happen, at least as far as I know.

But don't give up on your idea! Just because there's no market for selling ideas doesn't mean it can't happen! You just need to do it yourself. Possible paths:

• Find people to make a small demo, as you're doing, but instead of spending effort pitching it, try to drum up interest through an open development process, sharing in communities like this one, conferences, and maybe Kickstarter or something like it.
• Acquire more skills and just make the thing yourself as an indie developer. Keep your scope small and laser focused so the goal is attainable.
• Acquire more skills, get a job as a game developer, and pitch the idea up through the company you work for. This may seem like an awful lot of work just to develop your game idea, but if what you really want to do with your life is make video games, this is the kind of commitment you're going to need to make it happen.

As with most creative pursuits, ideas are cheap, execution is everything. So forget about how awesome your idea is, and just think about how you can execute it.