Maybe you will be interested in our 4th Edition Iron Tower Adventure Path, to be published through Paizo. That's right. Adventure Path. 4E.
It will be a continuation of what you will get a glimpse of in our free 4E pdf intro adventure "Winter's Tomb."
It will have a setting larger than that from Shackled City. It wont be a full world. Buy you'll be able to run a campaign in it.
Ancient frost giant ruins.
An aquirable stronghold for the PCs.
An epic weapon with a legendary secret.
Descent into the underdark.
Travel to the elemental planes of fire and ice.
And to the very gates of Hell itself.
Oh, and if you dont think we can do old school first edition feel with 4e, think again. I guarantee it.
I am so geeked to support 4E, I can't even tell you... And just wait till you see who is going to be helping me with this.