I would guess they move from a 28W TDP part to a 45W TDP part, but remain in the mobile line. That means an H series instead of a U series. Something like the i5-8300H (4 cores, 8 threads) and the i7-8850 (6 cores, 12 threads), with up to 64 GB of RAM, and the same ridiculously fast SSD as in the macbook pro line-up. Prices will go up by a significant chunk in keeping with Tim Cook's policy to keep pushing up the average selling price, but you'll get proportionately more hardware so it will probably be a pretty reasonable deal.