Are there any LEGO "MacGyvering kits" for the on-the-go LEGO fan?
It seems like you have the parts in mind, but really just need a case. 

I have used fishing tackle boxes and artist supply boxes, but the compartments were too narrow. 

Pros: Versatile, cheap, stackable, configurable. 
You can use the removable compartments as parts trays during builds. You can find them in various colors at the major discount retailers in the U.S. 

Cons: No handle. Not durable. If you drop or step on them, the hinges will crack. 

Dimensions


13 3/8" L x 10 3/4" W x 2 1/2" H
34 cm x 27.3cm x 7.9cm




Listing at the Sterlite website