Sure, you could have a go-pro or something, but it wont be anywhere near what people will pay for. They want the full overhead view so they can track the plays & the movement of each player - you're still not getting that angle from the nosebleeds.

Regardless, its an awful lot of work which is a) still illegal (therefore risky) b) difficult to market and c) completely obsolete the second the NFL network starts a new TV/online network for it