Jay -
Good topic, I've been dealing with this lately too. The three incumbent rod tubes seem to be:
KIS Australia - who is out of stock and has no clue when they will have more according to a large retailer who called them recently. It's square in profile, has wheels, handle, telescopes, and the large case is 7x7xlgt so you could put tubes in it if desired but it was MIS (pun intended).
SKB Rod Pod - who makes a nifty case that does not telescope - so it's always at 72" in length. Other than that minor flaw

it's triangular and well built. This case will not fit tubes within it, it's for rods in socks with added padding. If it telescoped it would be the ticket hands down in the absence of KIS.
Plano Bazuka - round in profile, not necessarily the roughtest of the lot (mine did not survive baggage handling recently) but overall probably the most feasible solution if you need telescoping ability to adjust to rod length. This case will not fit tubes within it, it's for rods in socks with added padding.
If weight is not an issue, then you can make a bomb-proof case out of PVC pipe. Choose your diameter, cut your length and put a screw plug on one end. It will definitely get security's attention, so check it as baggage.
You could lash the tubes together, I've done this often. The dents in the tube tell the tale of their rough journey though.
You might consider sending them UPS.