On another note, I never really appreciated what a cool ranged weapon the warhammer was until I saw an olympic hammer-thrower on television. That's so awesome!
I have no idea about the limits around intellectual property, but I'll try my best not to breach them and meet your needs.
I just realised that it only has d4 hit die and poor BAB progression, but 2 good saves and easy entry requirements.
Main abilities are +1 level to existing spellcasting class at each level, creatures of earth type friendlier to you, once per day divination spell-like ability drawing from the knowledge of the mountains nearby (no good if none near) at 2nd level, lesser tremorsense (10ft) at 3rd level, earth sight at 4th (can see through dirt and stone up to 30ft), and earth glide (like an earth elemental) at 5th level.
