I have been reading and working with your code last few weeks. I modified your original code.
Fixed ALL the bugs in front-end and back-end. (hopefully)
Added captcha to newsletter subscribe.
Added a contact page with captcha.
Updated to CI 1.7.2
Changed to jQuery.
Added a nudge menu to the front-end
Random feature products images have a link to product page.
Changed admin/products to show more details including categor names.
Search function do not pick up inactive products.
Added table-sort function (jQuery) to all the backend pages. This enables to sort in both ways, including show rows (10, 20, 30, etc) as well.
If I get your permission, I'd like to add to Codeigniter Wiki.
Of course all the credits to the book and recommendation of the book.
If you like I can send you a copy to see it first.
Please let me know.