Just received a call from Tesla as well and it looks like they are offering a free "upgrade" to the 6 seater option for any 5 seat Plaid orders. Unfortunately I'll need the extra trunk space, but might take delivery of it and resell, as I received $6,500 for free?
Email from Tesla below (sent after the call):
"Thank you for taking a moment to discuss your Model X order. We have confirmed that you will moving into the 6 Seat Model X Plaid configuration and you’ll be able to see the updated pricing within a few days. Your price adjustment will change again when you get closer to your delivery timeline."