Rather than lie with baited breath over 4e developments, are figured I may as well have some fun with what we know so far. And of course I invite you all to have some too. 
While we may not have enough information to start making house rules for 4e, we do know of some of the types of changes made and the overall direction of it. With that we can come up with changes along similar lines, that either are made to work with 3e as is or create some kind of hybrid system.
I'll start of with a basic one: the 4e loss of the full attack action. Supposedly this is meant to get rid of the mess of iterative attacks with multiple hit bonuses and such. I'm all for that in principle, but that would be tough to hammer into 3e so here's a different version:
-Whenever you would get iterative attacks, they are replaced with a single attack with a bonus to damage equal to 1/2 the users BAB.
-Other attacks, such as by a standard action or AoO, are handled normally.
-Bonus attacks are also unchanged, such as when hasted or when fighting with two weapons. However, the feat Improved Two-Weapon Fighting is changed to give the 1/2 BAB damage bonus to the off hand weapon attack during a full attack. The feat Greater Two-Weapon Fighting is removed entirely.
Other inspirations?

While we may not have enough information to start making house rules for 4e, we do know of some of the types of changes made and the overall direction of it. With that we can come up with changes along similar lines, that either are made to work with 3e as is or create some kind of hybrid system.
I'll start of with a basic one: the 4e loss of the full attack action. Supposedly this is meant to get rid of the mess of iterative attacks with multiple hit bonuses and such. I'm all for that in principle, but that would be tough to hammer into 3e so here's a different version:
-Whenever you would get iterative attacks, they are replaced with a single attack with a bonus to damage equal to 1/2 the users BAB.
-Other attacks, such as by a standard action or AoO, are handled normally.
-Bonus attacks are also unchanged, such as when hasted or when fighting with two weapons. However, the feat Improved Two-Weapon Fighting is changed to give the 1/2 BAB damage bonus to the off hand weapon attack during a full attack. The feat Greater Two-Weapon Fighting is removed entirely.
Other inspirations?