A BBC News team came across an abandoned Toyota Landcruiser in the Libyian city of Sirte which was outfitted with a remote controlled and fully retractable machine gun turret. The machine gun appears to be a HK21 (or one of its variants) and is fitted with two cameras. A local suggested it was used by the Gaddafi family. The engineering and electronics work looks professional, not like the DIY weapons being fielded by the rebels.
[ Many thanks to Tarkan for emailing me the link. ]