They are worth however much someone is willing to pay really.. This one cost £1000 and being in near perfect condition I would value it at double that amount based on the fact they only made 300 of them.
@Shiny-side-up: good to know. Some guy here was trying to flog off his well used and abused for NZD$7,500 (UKP 3,700). It was a mish mash of original and lower grade replacement components, badly scratched and dented. Naturally no one bought it.