Found this while browsing through Pistonheads classifieds..
DK Engineering : Mclaren F1 GTR - Road converted & Registered

Chassis number 16R, Mclaren F1 GTR converted to roadcar. This is the same car that featured in the Fifth Gear episode along side the Ferrari Enzo Ferrari.

Anyone have a few million pounds spare? No price quoted, but I dooubt it'll be cheap.