What about MBP with a 24" or 27" IPS monitor for docking at home?
If rMBP + ATD is a budget killer, I would suggest a cMBP or even high end MBA with ATD. The reason is most photographers will likely spend more time on final editing on a large monitor at home or office than they will on the laptop's native screen.
A nice 27" IPS monitor like a Dell U2711 will cost around $700. And it will provide no thunderbolt docking features. For $829 you can get the 27" IPS monitor and thunderbolt docking, integrated camera for FaceTime, and speakers. You can also optionally get Apple Care for it (less than $75 at B&H). If you purchase the ATD at the same time as a MBP, you get them both under the same Apple Care coverage.