Unfortunately, I don't know of any suitable ebooks available other than the ones which you list. There are a number of public domain texts on archive.org (search for penmanship, italic, cursive, &c.) but none which really address modern needs.
One of the best books is _An Italic Calligraphy Handbook_ by Carolyn (Knudsen) Joy Adams:
http://books.google.com/books/about/...d=_xzWAAAAMAAJ
Tom Gourdie's _A Guide to Better Handwriting_ is also quite good.
Either of the above is well-worth finding in print.
Rosemary Sassoon's writings are also quite illuminating.