When I went to TDL in 2001, I saw no guidebooks, videos, or anything of the like for sale. But when I came back I found someone running an online store of TDL merch. and got a video through them.
First, does this store still exist on the web? I can't find it.
Next, do any books or videos currently exist? How about one of those independant magazine like guidebooks that one can buy in stores around Japan? I remember seeing a ton dedicated to parks when I was there (usually covering many parks)