Once in a blue moon the official site actually does something interesting. They've started a new series of articles called "Empire Chronicles" that features spotlights on different aspects of The Empire Strikes Back.
Based on the first article, it looks like they're just pulling quotes from various interviews and articles throughout the history of the film and putting them together in a new article with various interesting pictures. So, while it's not necessarily new info, it is interesting & presented in an appealing way I think.
It's also interesting to note that it appears they're not going to be totally revistionist...
George says this about the AT-AT:
"The walkers, if anything, were inspired by the original novel of War of the Worlds where the Martians walked on giant spiders that walked on legs."
And immediately after George's block, they have this from Joe Johnston:
"I did a bunch of sketches using the tanks as a basis. Then I ran across a xerox that a friend of mine had. It as a promotional brochure put out by U.S. Steel in the early Sixties and contained a whole slew of full-color paintings indicating 'what steel will be used for in the future.' The paintings were done by Syd Meade. Interestingly enough, one of the paintings showed a four-legged walking truck! That's where the initial walker idea came from."