Yeah but yeah but yeah but, oh what the hell...
If it is for those types of productions (Life, Planet Earth etc etc) then they will either hire the camera for you and pay you to go film it or they will send one of their own guys to film it. Either way you don't need an all singing all dancing camera for that because you will either get the gig all equipment provided or they will bypass you entirely and send someone else!
They rarely ever buy footage off the shelf for top end productions where there is an absolute requirement that they wont go below a certain spec as they would rather spend £xx,000 more to go get the footage themselves. The famous Mr Scones story of the BBC sending him to Borneo or wherever to film diving monkeys but the puddle they were swimming in the year before had dried up springs to mind! They spent thousands just so they didn't have to buy the footage off of a French production company (although ironically in the end that was a rare case when they did have to buy it in!).
I guess all I'm saying is that if you want and/or need a certain camera for your own productions then get it, but just because it is or isn't on a BBC camera list doesn't mean that you will or will not be able to sell footage to them.
I know we're on the same page here, so I'll shut up. Lips firmly sealed. Never gonna respond to one of these posts again. Never ever. Honest. 
Cheers, Simon