I really love the idea of a book like you have described. I have Lee's book (Universal Tarot of Marseille) which is a great starter but I'd be happy for more. I suspect what you are suggesting is an extended version of something like that.
I agree with LRichard that the market for this type of book is fairly slim, tarot is a small market to begin with and those interested in the historical side of tarot even slimmer, but I don't think that should deter you at all. Also, I doubt making a lot of money is your motivation anyway. When you are passionate about something, sharing is half the fun.
I'll put my comments below, hope it's not overkill.
Here's a question for everyone who wishes there were an inexpensive, easy to procure, beginner's book on the TdM in English. What would you like to see in this book? I'm asking because I'm considering writing such a book.
The French and Italian beginner's books I have on my shelves are structured very much like beginner's books in English for the Waite Smith deck. Here's a list of what they contain. Help create your ideal book by telling me which of these features appeals to you and what else you want to add.
For starters I love the idea of a beginners book that has nothing to do with the Waite Smith deck. That alone would be worth buying regardless of what content is in it.
One or two pages on each card, with a brief description of the image, then divinatory meanings for each card.
For the trump cards: discussion of the symbolism of some of the details on the card.
I'd love quite a thorough discussion of the symbolism of each card and how this could be used in a divinatory sense. What I like about these decks is getting a sense of what the imagery would have meant to people at the time of their creation.
Spreads
Sample readings with each spread.
I've never been a huge fan of spreads or sample readings in books and tend to just skip over them, but including this wouldn't stop me buying the book.
Cards pictured in sets of two or three with a discussion on how they interact and modify each other.
This appeals more than spreads and sample readings actually. I think this is an area of tarot writing that is pretty under-done really.
Definitely!
Correspondences: astrological, elements, hebrew letters, numerology
Tricky one as there are so many possibilities. I like the idea of some information that shows the many variations so that people have the confidence to know they can work out a system that fits for them. Discussion about the suit implements themselves would be interesting.
Mandalas and tableaux using the entire deck.
Really like the idea of this, especially info re using a tableaux.
Games and exercises to get your intuition flowing.
Mabye, but this wouldn't be a big drawcard for me.
Would your ideal book be for one specific deck or generic so it could be used with many TdM's? European books seem to default to the Grimaud TdM if they aren't dealing with a specific deck. One of the larger books I have illustrates the trumps with 4 different cards, but this is unusual.
As mentioned about I'd love a book that was generic. I actually use the Ancient Italian which has some different symbolism to the TdM's so would be great if the info was broad enough to still be helpful for that deck. Having a book that used illustrations from a variety of decks would be fantastic, but not sure how challenging that would be with copyrites etc.
How about a book that does not contain divinatory meanings (or puts them in a list in the back instead) but rather takes you through a course of exercises to help you come up with your own understanding of each card (much like my tarot-heritage website does).
Personally I use Paul Huson's Mystical Origins as a reference for possible divinatory meanings and so would be happy for them to be listed at the back. I think the idea of exercises like you mention is a good idea for beginners as well.
It would be great to have some discussion on the courts as they are tricky at the best of times but can be even more so with a TdM, for some people.
Ultimately I think a lot of stuff about how to read, developing intuition, correspondences has been done to death in a lot of books. The history and the discussion of the imagery in a historical context with a view to divination is what hasn't been done as much. I'd stay narrow rather than going too broad to ensure that you really connect to the niche market that is going to be drawn to the book.
Just my thoughts anyway, hope they are of some help.