I'm curious. What do you consider to be "high level"?
Because an elven Mage, using level limits by RAW, caps off at 15th level. And if this same elven Mage has an 18 INT, and the optional rules of exceeding level limits is used, caps off at 18th level...
Either way, that's fairly high level if you ask me!
YMMV and all of that of course...