Yes, switching the covers on a number of identical books seems a good alternative to having three special books (Flashback books, is that the term?). Three special books (flashback?) entail, among other things, having to keep track of three sets of numbers to force.
Thanks Paul for the reading suggestions !!! I, for one, will have to look at ALL the suggestions (this forum is certainly detrimental to my finances).
Still, its nice to have a repertoire of special books for those times when you visit someone and can borrow something from their own bookshelf (make sure to give everyone you know a Flashback book for Christmas. And dont forget to wait for a couple of years before doing the trick).
P.S. There is a review of Silver Bullet at: http://www.online-visions.com/reviews/0212sb.html
It should be said that the VISION review is not favourable. I also looked at some of the posts at the Magic cafe http://themagiccafe.com/
where there a lots of people with very favourable views of the product/gimmick/thing.