True - and point of fact - I think there is definitely room for a 'generic' low-magic setting book for 3e.
As for using 'established monsters' for a low magic setting, don't the 'established monsters' all presume a high magic setting, making them somewhat intrinsically flawed for use in a low magic setting?
O.k., says you, that isn't very useful, T.S. I still want to use a damn (fill in the monster), low-magic or no.
Fine. Presume you have an all fighter party in a "standard" game of 3e - following your [jmucchiello's] magic assumptions- what is the difference?
Well, their weapons/armor wouldn't have as high a bonus, and special abilities would be unlikely. Their access to healing magic, presumably potions, would be less. Low-magic settings already have to contend with the "hit point" question, long before they worry about magic items.
In most cases I would adjust the hypothetical monster by lowering its armor class, BAB, and Str/Dam.
Or not - some GMs are cruel that way.
My thought to you, is what happens to game balance between a fighter and the other classes when you adjust their magic abilities downward without corresponding compensation?
Which is why, returning to my first point, I think there is definetly a place for a generic low-magic setting sourcebook - one that redefines all of the core classes for use in a low-magic setting.