I think a boxed mega set with miniautres and nice maps and pre-printed fold out mats with one inch grids would be totally cool. Except for one thing: I already own all of the adventure path modules and a couple of them are real stinkers.
Here's a better idea, in my opinion: Write a mega module. Make sure there are statblocks of creatures and treasure all on the entry they are encountered so I don't have to fumble through my Monster Manual or flip to the back of the book to look up details in an index, include double sided paper foldout mats with a one inch grid and make sure the maps in the book are 1 square = 5 feet... I'm so sick of publishers doing different scales... include miniatures suitable for the Minis game or just for use as tokens in the adventure. Include a couple of special creatures, you know, what WotC is releasing as rare (large creatures for instance). Include the cards for the skirmish game. Maybe include some special skirmish scenarios in the back of the book for the minis crowd to use these minis and mats with preprinted terrain. Voila. You have crossover appeal between regular D&Ders and the skirmish game addicts. It also gives folks that have been reluctant to try minis an opportunity to do so without shelling out 30 bucks for a Battlemat and pens and another 10 - 20 on minis. Ta-da! This I would buy in a heartbeat. An (almost) totally self contained campaign in a box. Still requires using the PHB and DMG, etc. but we are assuming that most folks who play D&D already have these items. If the "D&D Basic Set" comes out, have a conversion document and or dual stat the book. Seriously WotC, you need to do this.