The only hard part would be getting the book spines to look nice and find a way to place the linkable text on it so it looks classy.
This is not technologically difficult, but could be a bit time consuming if you want to make really cool-looking books.
Since the book's spine is all that's really visible on the bookshelf, the entire spine's area will be mapped to the URL. The text of the book title doesn't need to be linkable text, since clicking anywhere on the book's spine will complete the link.
That means that you can draw, paint, photoshop, or whatever technique you like to put the titles on the books. You can even paint full-sized original images of each book, scan the art work and then photoshop it in place on the book shelf. Then all you need to do is image map a rectangle around the book's spine and it's ready to use.
If you want to make the titles glow or something when the cursor is rolled over them or clicked, that is possible, but I wouldn't recommend it because it will make everything much more complicated. This is because you'll then need normal-text and glowing-text images of each book. Also, instead of working with just one 2D image, each book will have to be a separate image and they'll all have to be tiled together. That's so the image corresponding to one book can be instantly replaced with a glowing text image of the same book. Although do-able, it would be a nightmare and it would also make any additions or subtractions much more complicated. I suggest you forget about glowing text, and I'm sorry I brought it up.
The idea of opening the book to reveal additional links is nice and not too difficult. To do that, you would just replace the original bookshelf image with the exact same image except with the selected book shown opened in the foreground. Then it would be your choice whether to use standard html text, or exotic, hand-painted text for the link list. You can use tables to position the html text over an image background, or you can use your calligraphy skills to hand-write the links and image map them to the appropriate URL.
Neither of those options are technologically difficult and they are both pretty flexible.