Go into engineering, get hired by AMD or NVIDIA. Maybe by 2020 they'll let you help build a real one.
Anyone who needs to ask how they go about it on Toms hardware doesn't have the slightest clue what they are doing, no offense. You're talking an "idea" in kid terms. One that any engineer would tell you after 3 minutes defies the laws of physics, electricity, economics, or common sense.
I know what i'm doing, and my idea isn't complete innovation, its just using what is already there and putting a twist on it, there is no fundamental architecture change from a normal GPU just a new way of doing it.