Konami are hiring for MGS 5, which looks as though it could be a remake of Metal Gear 1. It looks like it will definitely be a older Big Boss in it, anyway!
How do people feel about a MGS with snake? I don't think it could work well, personally. It would have to have some cliche 'nanomachine age reversal', and all the enemies/loose ends are pretty much tied up in MGS4. But part of me would like to play as snake again on a next gen system, they really pushed the PS3 hard with MGS4, and that was released in 2008, its rare a developer gets close to the edge of a machine's potential that early in its lifespan. On a PS4 it could be staggering.