That may be true, but Apple also updated the MB's in May 2007, and the MBP in June 2007. However, the MB didn't get Santa Rosa until the November update. It would be unusual for Apple to release Penryn in both systems on the same day, much less on the MB before the MBP. I definitely believe that the new MBP will be released first, and if not, then it is because Apple has consolidated the MBP and MB into a single line, with Pro BTO options in place. I actually hope this is true, as I could order a 13" MB + Pro options, mainly a 256mb graphics card. If they do this, most likely the 13" Pro options will be limited compared to the other sizes, for the obvious size constraint reasons.
I also doubt 13" MB+P sales would cannibalize MBA sales, as the MBA would still be much thinner, lighter, and cheaper. The 13" MB+P would most likely be slightly more expensive then the base 15" model, probably at least $400 more expensive than the air.
"Introducing the new Macbook. Add a little Pro to your life."
Hah, that's the best I've got at 3am on a Tuesday morning. Too bad my workout tonight didn't knock me out like I'd hoped. I'm way too excited to sleep. I need a pill. I've got 11.25 hours of class tomorrow. This can't be healthy.