Hey Robert !
I just did a shoot for Lufthansa in a VIP-737(one of those things people with too much money get for themselves when they get bored
I do have a Baerbel as well and I can tell You it´s possible but You might be in pain!!!! the 747 is bigger,but You definitely should take some old foam-matrace with you to cover the arm.Just cut it into pieces as you need it and tape it to the arm.this will take the fear of damaging the aircraft interior away.
If you have a lite camera as for example a HD,you might even be able to do low mode if you use the normal post,with sushi-server and heavy batteries,because the 747 has a bit more headroom.
Walking through the plane is quite exhausting,because you will have to work quite far away from you body.
You might find it comfortable to walk sideways.(zick-zack)
The main problem might be the arm touching the chairs.If possible put them into a lower position.
Panning was not a problem for me,but it was painful.
If you need more detailed answeres ,just send me a message or better a personal e-mail (firstname.lastname@example.org ) because it might be easier for me explaining it in german
Going to CINEC ? I´ll be there at the stand of Gripdepot !