http://www.vangadgets.co.uk/index.html? ... system.htm
I reckon, these may overcome certain bikes' (like my TT's) crap rearview capability.
I can only assume, that they'd be legal for use, as there are big cars that use them on the road (Mercedes trialled them I think? and some sportscars)
This would do away with the need for rear view mirrors, streamlining the bike a bit at the same time.
Im sure it'd be possible to fit it to a sportsbike, defibately a bike such as Gio's big BMW thing.
Prices seem quite reasonable too.

Maybe it would be possible to move the camera to the front andtake the feed out to a recording device for trackdays?