If you specialize in something it would be easy to make much more money. Once at the two year mark as a CFI you can train other CFI's. Most airline bound guys are gone by that point, so you should get a premium for being qualified for that. Getting trained as a cirrus instructor would get you into that market, though I'm not sure if the cost is worth it. Just a guess, but I'd think $40-50/hr for CFI instruction and $80/hr as a cirrus instructor would be reasonable.