Been mulling over tidying up the tail (shortening it) for ages. Not really keen on the aftermarket stuff and I kind of like the OE tail light design. Didn't want to do anything that would leave visible scars on the bike should I want to return it to standard. Had an old Touratech splash guard for my long departed GS (that I never fitted) kicking around in the shed. After much head scratching I came up with this not exactly radical tail, but it's another idea...
Basically it's the TT splash guard (with about 2 inches trimmed from the top) mounted by the bottom holes (not the top) to the existing number plate hanger. All I had to chop off was the (unecessary) thin, lower bit of the mudguard below the hanger (no drilling required). Add a discrete LED number plate lamp on the splashguard's lip and homemade aluminium bracket for the OE reflector and that's it. A standard UK plate fits without obscuring the indicators in their standard position if you put a few scotch sticky pads on the back of the number plate, which brings it forward 3-4mm to clear the cutaways in the OE indicator lens (the spashguard is narrower anyway as its German plate width). A small bonus is the lip on the splashguard does a good job of catching the extra muck flicked up from the shorter mudguard.
To return to standard just mount the TT splashguard/numberplate in its normal position, replace relector and refit OE numberplate lamp. The small cut part is invisible behind the numberplate and the splashguard.