http://www.tartopper.com/
The Tar Topper is a cover that goes over the top of an Optima or a Delco/Exide/NAPA flat top Group 24 battery and gives the appearance of a genuine tar top unit.
It's intended for American cars so it may not have the exact look of the OEM Italian batteries, but at less than $30 it's quite a bit cheaper than Tom's repro unit.
Todd