Here are some pics of my "Pack along in the luggage" Field / Pit Kit. The box is 6" X 9" X 4" deep. Smaller box was just a lucky find that fit.
A handle, several sets of lines,fuel syringe, glow driver, and a Leatherman multi-tool (both in belt holsters) are all right there when you open the box. There is also a retractable razor knife, some ca, and a small tin of hardware/ glow plugs.
Smaller box under handle / syringe holds wrenches, multi bit screwdriver set, a torque screwdriver and bits for engine assembly and checking fasteners for security. A few misc tools,spare needle valve assy,alcohol wipes for cleaning lines, Ni-starter charger, etc fill the rest of it.
Takes up less room than a pair of jeans in a suitcase, weighs less than 5 lbs, and except for the Torque screw driver kit everything in it could be replaced for about $100. If you have nicer equipment, and don't want to chance losing it in your luggage - you could ship it ahead, nothing in there is prohibited or Haz-mat to cause shipping issues.