This is why I got to level 5 in crafting - it helps alleviate the problem for spell casters, at least.
If you can find a scroll of the spell you want, you can craft the book by putting the scroll in a blank skill book of the same school. To make the blank skill book, you combine blank scrolls of the same school(so blank air x 2 = blank air skill book). This is how I made white wolf and summon skeleton books (I still haven't seen them in shops). The only problem is you can't control what kind of blank scroll you get when you put pixie dust on paper. It's a 20% chance (I assume, given there are 5 applicable schools) so it can take a lot of mats (or a lot of loading) to get two pages of the same school.
