Ok, two weeks ago, I had to carry my ST2 from DC to NY and I was researching on this topic.
I was able to fit the ST2 in the trunk of Ford Fusion (w/ front wheel removed)
I was looking into this box but then realized that I will have to remove front fender, rear fender (has rear light connection) and it becomes huge hassle to get everything back up.
AirCaddy or XLBikeBox is the closest I can think of.
Last December, I took an eBike from DC to India. I packed the bike in a box similar to AirCaddy and kept the battery in carry on bag. Up to 300Whr is allowed without requiring any paperwork.
You're right. Sorry for the typo. I think I got lucky re: carrying the battery
OEM's pay HAZMAT fee of $35-$50. perhaps you might want to ask your dealer get that part sorted out.