"For travel and outside clients..."
I'd have to question
any solution where you are trying to include color grading. Color (app) by design really requires,
Display with 1680-by-1050 resolution or higher; dual displays are highly recommended, you don't have that on the MacBook Pro. You should have a control surface and you also should be working in a room that is properly set-up for color correction. But, yes, the MXO would be your option and you still need a monitor which is supported.
If you simply want a solution so you and your client aren't crowding over a 15" laptop screen then the
Dell UltraSharp U2410 (1920x1200) is likely your best bet.