It was a 3am idea, so probably hasn't got much milage in it - but if one bought a five speed Brompton, used of course, would it be possible to fit the 2 speed Brompton derailleur, and end up with 10 gears ? Wadda ya think, move over Steve Parry, the new Brompton Messiah is coming through, or shall I just go back to bed ?

This has already been tried... have a look at the online version of A to B, August 2006