Geoff:
Here is link to Stanley site, I think these plastic face hammers are what you are after, I have one that has lasted dang near forever. According to Stanley you should be able to find them at an Ace Hardware Store. Because of the smaller head size I find them handier than a dead blow mallet. :wsmile:
http://www.stanleytools.com/default.asp?TYPE=CATEGORY&CATEGORY=SOFT+FACE+HAMMERS&PAGENUMBER=2