Indeed! And I like your examples. I take it that mages are only allowed to buy spells if they are part of a known style?
Here is a GURPS setting I worked up some time ago using 31 different magical styles. My styles assume that any skill or spell
can be learned by the mage, but some are required to complete apprenticeship, so everything in the style is required.
http://wiki.rpg.net/index.php/The_Gift:Main_Page
I'm working on another one right now (as in, I was doing it when I read your post). The new setting will only have 27 styles. :)