NCrunch doesn't have any offline documentation at the moment (as the docs are in wiki form), but I could certainly see how this could be useful.
The documentation will be getting a major overhaul soon, with much of the content rewritten and all of it placed within a new proper table of contents. I'll have a look to see what effort would be involved with packaging a copy with the application.
Some allowances were made for this during the documentation revision last year, although as few people have asked for it there are no plans yet to address this in the near future. Thanks for providing your vote on this as I do take this into account.