A forum poster by the name of Borman over on the Assembler Games forums has in his possession both a PAL and NTSC beta copy of Perfect Dark, and a build as well as a demo version of Conker's Bad Fur Day.
Most notable here is that Conker's Bad Fur Day includes many explicit, uncensored scenes that were later removed from the retail version of the game. In the video above you can see the Tediz operating on a live squirrel soldier. That scene is non-existent in the final version, for obvious reasons.
Borman will release all four of these builds to the public after they've raised $2,500 in a charity drive in order to recoup the costs of obtaining these rare items.