Dean,
ESCI used to make a Sherman Calliope but the Italeri kit doesn't come with the rocket tubes. Al.By made a conversion for this version but not sure if it is still available. Check through this site. If it is available in 1/72 they usually have it and I have heard good things about their customer service.
http://www.tracks-n-troops.com/1-72%20Armor.htm
You can also find some good reviews here
http://www.ontheway.us/default.htm