I think it'd be cool if they released "Basic 4E" adventure modules for a reasonable price.
Each adventure module would be designed to capture the new "feel" of 4E, and perhaps act as a bridge to some changes they'll make from 3.X to 4E.
In these Basic 4E modules, they could have 4-6 premade characters with stat blocks, no rules on character creation (that way no one will pass on buying the PHB), and very brief rules for updated combat that reflects how the system differs from 3.xE
In fact, break it down like "Basic DnD" prior to "Advanced DnD".
i.e. The basic characters are a Tiefling, Human, Halfling, Eladrin, Dwarf, etc... The Tiefling has Warlock like powers, the Human has Wizardly powers, the Halfling has Rogue powers, the Eladrin has Cleric powers, etc...
Not only would this take minimal effort (heck, I'm sure a lot of people would volunteer to write the adventures) and get the fanbase excited about "Advanced" 4E (I want to play a multi-class Tiefling Rogue, not a Warlock!), but it would also act as a buffer for playtesting and the ultimate release of 4E.
Actually, I'm a corporate software trainer and QA tester...and no matter how long or thoroughly my team QA tests a new version, the customers ALWAYS find issues/bugs/enhancements that we completely missed.
By releasing "Basic/Beta" 4E, they would essentially get an additional level of QA testing on their product...QA testing that people would PAY to do!
Just a thought.