Did the 3500 mile version back in.....erm, I think 2003 on my VFR800. In 4 days. Can't remember exactly how many hours, but I think something like 78 hours riding in 96 hours.
Missed out Skye, Anglesey and a few other gnarly bits. Raised a few grand for cancer charity back then. Very knackering, but mostly enjoyable - except for the midges.
Not sure if I could do it again, there was a few times I was all but falling asleep, and 14 years on my stamina is probably nowhere near good enough. If I had time I'd like to do the full 10k version, maybe over a good few weeks though.