From everything I've heard this seems extremely unlikely. In a post here at EN World, it was confirmed that there were exactly 8 classes(and this post is AFTER the comment that there might be more). It's possible that changes, but I'm going to assume it's true unless someone says otherwise.
We know that Fighters, Wizards, Rogues, Clerics are in for sure. One of the playtest reports, I believe (even though it doesn't say for sure) is one of the groups running ONLY PHB1 stuff. In this playtest they mention rangers and warlords. Paladins are mentioned so many places (including having meetings about the paladin and fighter, comments about the paladin being a defender and about it being able to choose any alignment it wants), I believe it's basically confirmed.
So that leaves only one class space. At this point it seems likely that the last one is Warlock(comments about how having the Tiefling in the PHB1 gave them heavy incentive to include Warlock in there as well, and the recent blog about the fact that development for the Warlock is finished and they are working right now on its description).
That means that the nearly confirmed list of classes in the PHB1 is:
Fighter
Paladin
Warlord
Cleric
Wizard
Warlock
Rogue
Ranger
And due to the comment of at least one (if not multiple) designers that ALL the PHB classes from 3.5 would eventually be put into 4E, I don't believe the Druid will be rolled into the Cleric or the Bard at all. Nor will Barbarian be rolled into Fighter.
I have a feeling that the PHB2 will include the rest of the 3.5E classes from the PHB.