We've had it before, back in the Giro in the late 1990s, when a camera was placed in the seat post of a bike. Needless to say, it wasn't very good and the main thing I recall about it is a vague feeling of seasickness from all the swaying.
HTC Highroad have done it before with Go Pro cameras.
HTC Highroad have done it before with Go Pro cameras.
It was on youtube ages ago.