Have you checked W.J. Rawkins' The Army of the Kingdom of Naples?

It has much information on the organization of the different regiments plus their uniforms and is 186 pages long.

It can be bought as an ebook for £4.50 from the History Bookman.

You can see a review of it at:

http://www.napoleon-series.org/reviews/uniforms/c_rawkins1.html