Hmmm... I'm thinking I might do something similar. I'm heading out for a business trip soon, and plan to bring the Brompton. I might pack my saddle into my carry on since it's relatively dense but not extraordinarily bulky (compared to the helmet). I can put a few more things into the B&W case then (e.g., liquids).

Scooper, do you bother providing any extra protection, such as wrapping up the body hinges, or taping up the fenders so they don't bend if the bike shifts in its case? Thanks.