Some links I found while working on this dress:
The Realm of Venus
http://www.renaissancewoman.net/realmofvenus/
Many pictures, specifically focussed on Venice, but many things
apply to other parts of Italy.
section on making
camicias: http://www.renaissancewoman.net/realmofvenus/seamstress/camiciahowto.htm
Festive Attyre
Florentine portraits 1525 – 1550: http://www.festiveattyre.com/research/secondflor/portfolio.html
A Florentine dress diary : http://www.festiveattyre.com/research/diary/diary.html
The Zen of Spiral Lacing: http://www.festiveattyre.com/research/lacing/lacing.html
The Renaissance Tailor
http://www.vertetsable.com/
Not necessarily Italian, but very helpful for techniques – check
out the demos section : http://www.vertetsable.com/demos_main.htm
Italian Renaissance Gown Construction
http://homepages.wmich.edu/~rowen/renbk/rendressbook.html
Simple directions for making your own Italian Renaissance gown, including
directions for making the puffy-top sleeves! (I don't agree with them about
the boning, though)
Wikimedia Commons
http://commons.wikimedia.org/wiki/Category:Italian_Renaissance_painters
Some really good scans of paintings.
Recreating History
The chemise: http://www.reconstructinghistory.com/beginners/chemise.html
Another easy pattern for the chemise or camicia