what are you total size restrictions? Why are you not able to pack a full controller. There are really specifics you need to answer.
If you are plugging into an existing club system (mixer and CDJs), an X1, midi fighter and an audio 6 with timecode is the most portable solution. You will already be bringing a laptop with you, and there are lots of controllers that will fit into a laptop bag.
What are your limitations? Weight, Size, Volume, Walking distance etc?
I have a Traktor S4, Midi Fighter Pro, Launch Pad, Laptop and it all fits into 1 carry on luggage bag, all cords and everything packed rather perfect.
Link Below is the bag i use
http://www.mec.ca/AST/ShopMEC/Packs/TravelPacks/PRD~5024-301/mec-terabyte-roller.jsp