As a follow-up to my previous post about using the classes from the core books here is a list of them that I think will fit the setting.
I read through the System Reference Document and the usage guidelines for material there are pretty clear:
To remain in compliance with the GSL, you may not reproduce any running text, statistics block, or table from the Core Rulebooks, nor may you define, redefine, or alter the definition of any 4E Reference.
To remain in compliance with the GSL, you may not reproduce any running text, statistics block, or table from the Core Rulebooks, nor may you define, redefine, or alter the definition of any 4E Reference.