Suppose a well-off libertarian compiles a list of a hundred books that do a good job of promoting libertarian ideas and are not currently available online, goes to the publishers and offers to buy the online rights. Most books, including most books about ideas, do not make all that much money, so my guess is that a publisher should be willing to sell the online rights for ten thousand dollars, perhaps less. A few will be books that were or are best sellers, and their rights might be expensive—but those are books that most curious readers can probably find in the local library, so although webbing them would be useful, it would not be as useful as webbing less successful books. Cross them off the list and replace them with a few less expensive ones. Total cost a million dollars.
Well, I have a pretty big book collections these days, although not as colossal as that of Brian Micklethwait of this blog, or the late Chris Tame (he had the sort of private library that was mind-blowing, and that was just the science fiction bit).