Hi there
I think You rather exaggerated with the amount.
Everybody can provide 6 custom shot images, of different topics, and sometimes including hiring models (even Your family) and special posing, but I do not suppose the images are going to be professional ones. This work is highly special and demanding, even if You want just satisfactory, not the best results.
But, good luck with it, if You do.
My proposal is 1 vineyard image (all from Tuscany, Italy, Europe). The price is for that image (as for book cover, believe me - You are paying the best price now). Please find the 8 samples attached on PMB.
I do not sell Copyright. What did You mean by that? As I think it will not be possible... If You invented a product, will You sell the Copyright? You sell this, book (I assumed it was Yours). Now You go to the publisher to earn by selling LICENSES or ROYALTIES to the books, but they say: I will give You 100$ for all the books, and we will take all the earnings. But we will write those book are Yours.... How would You feel? You would have to go to office to write another book fast to get 100$ again...
Kindest regards