I just want to point out two new blogs that you may be interested in viewing.
The first is a Blog by Don Kuramura, Product Manager, with documentation explaing how to skin (or style) vB4:
vB4: Skinning Your Forum in 10 Easy Steps
The second is a Blog by Joe Rosenblum, CTO of Internet Brands, Inc. of special interest to the vB Development community:
Dear vBulletin Developers...
This is just the beginning. You can expect more like this in the future.
More...