I've been working on this with my collection of Italians. My goal was to eventually do l'Eroica in Gaiole on a different bike from each decade prior to the 90's (4 done so far).

1910's Touring
1920's missing (except for the wife's Gloria city bike)
1930's Airolg, Vittoria Margherita
1940's Legnano, Cambio Corsa
1940's Gloria Garibaldina, Simplex
1950's Cicli Masini, Paris-Roubaix
1960's missing and unfortunately not my thing(!)
1970's Ciöcc
1980's Tommasini Racing
1980's Rossin Ghibli
1990's Somec MS
2000's missing
2010's Colnago C60

Glad to see someone else is thinking along these lines! Makes me feel less compulsive!