What about a hammer with depleted uranium in the head for extra
weight. Much like this golf club:

http://www.timicom.com/timinews2.asp

Comedy that may be. But maraging steel, previously only used for
uranium enrichment centrifuges, is available for golf clubs.

http://en.wikipedia.org/wiki/Maraging_steel#Uses

Now if you can find a maraging steel hammer, I'll be well impressed.

Maraging steel is considered a military technology though, so no
taking it with you on contracts to knock up a few sheds in Iran.