I'm an Italophile also. You'll have a hard time finding the higher end stuff in a complete bike for $500 but you may luck into a CL find with some patience. A nice Rossin is on my wish list. These are quality frames (Rossin was an early frame builder for Ernesto Colnago) which don't command the premium of some of the other Italian makers. Moser has a hit or miss reputation, but I really like mine with Columbus SL tubes.

As noted above, the Merckx Century was designed specifically as a quality bike with more relaxed geometry. Not Italian but hey, it's Belgian and designed by the Cannibal! (Or one of his minions)