The hardcover, full colour version of An Introduction to Shinto is now available from Amazon. (Affiliate link)
It is really expensive, because of the cost of colour printing: $59.99. In addition, because of problems with the ISBN, I am afraid that I will not be able to make it available from any outlet other than Amazon in the near future. I would like to — the electronic version is available from Gumroad — but regulations make it impractical.
It takes them a long time to print it, but the images in the proof copy, at least, were good quality. It is definitely better than the black-and-white paperback, but it is also triple the price. You will have to decide for yourself whether it is that much better.