Last year I spent a lot of time traveling to China. I had similar concerns. Additionally since I was carrying a laptop I wanted my carry on bags to be lighter.
On one trip I piled all of that stuff 10D, 17-40L and a 24-135SP plus my computer into my backpack. Power supplies, batteries and such when into my checked bag. I would have LOVED to have my 100-400L... but made the decision to leave it home.
For subsequent flights carrying the same lenses I packed them in my luggage in protective bags, inserted into the middle of the bag for the most protection. That being said, I would have loved to have a special camera case to be able to check.
One thing, however, don't lock the case. If you lock it, they will want to open it. Checking is always risky that way. Perhaps take a picture of what's in the case and make sure that your luggage is insured properly when you check it in. Even show the picture at the counter, as the counters are photographed you will be building an audit trail.
This technique worked (not the picture) as I also travelled with a scanner valued at about $25,000 without problem. I carried that from China to HK and around Asia. It was in a separate case similar to the case recommended in someone else's reply.
Just some thoughts. best of luck!
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