I don't think there's much demand for a GE:S Steam skin.
One man's meat is another man's poison, and when you consider how small the minority of people who actually use custom skins for Steam is, and then out of those minority of people who would specifically like a Bond / GE:S styled skin over some generic flashy skin that blends with their Windows 7 theme, you realise it would not be a worthwhile endevour.
It's not something that can just be quickly slapped together with images pulled from google and be called 'decent' by any standards.