Contemplating a new RPG

I've been thinking about creating a new Role Playing Game. The idea for a one-shot type game came to me last night. I haven't really thought it all through yet but I'm still rather enamoured by the idea so I'm going to lay out the idea here so that it wont be lost.

The premise is a sci fi game where the players are super rich characters who like to hunt. The game starts with the PC's being dropped off on a remote planet by a shady guy who's promised them the hunt of a life time.

The game is simply the hunt. Other than the PC's the only other characters are the alien creatures being hunted.

I'm thinking that the Alien should be rolled up at the beginning of the game. This rolling up would consist of simple picking a collection traits/aspects that the GM would have to combine into some suitable target of the hunt.

The PCs would not be aware of the aliens aspects ( the shady character didn't give too much information ).

I'm thinking that the PC creation would be a little more complex. A small collection of skills would be available to pick from. Then they get a couple of positive traits/aspects and one negative. That would allow the PC's to be generated quite quickly which is required in a one-shot scenario.

Another variable that could be decided by a die roll, would be the environment, anything from swamp through to deserted city.

So that's the idea, a simple one shot game. I'll probably throw together the first draft of the rules in the near future, if I can find the time between work and recording audio books.