Yeah, I just checked several sources and they don't seem to carry them any more. Probably not enough demand. There is one on ebay that is rediculous at $189. Dictum has one for about $100USD, and of course there are the Japanese tool companies that must still be upset over WWII if you look at their prices.
As I said before, it is so easy to make one that it is almost foolish to buy one unless you want a specific hammer ( like a Salvati).
Simplest method:
Buy a hammer like the below examles. They can be found at almost any hardware store, hammer supplier, ebay, HF, yard sales, etc. You don't really need a high grade name brand.
http://www.ebay.com/itm/Vintage-ant...144060?hash=item1a33f993fc:g:IScAAOSw6WVZoWhJ
http://www.ebay.com/itm/Vintage-12-...282853?hash=item25de0e82a5:g:kz4AAOSw8thZmeeo
Cut it across the back of the eye section, removing the cross peen. You can use your metal cutting band saw ... or clamp it in a vise and do it with a hacksaw.
Grind it with a 60 grit belt and clean up with 120 grit.
You can do all that with the handle on, or remove the handle and reinstall/replace it if desired.
More work, but better hammer:
As above, a trip through ebay with a search for blacksmith hammer head, blacksmith hammer, or forging hammer, will find many cheap old hammer heads that are perfect for re-shaping. Some can merely be cut off and touched up as above, and others can be cut off and the long end re-forged to the shape desired. An old hot cut hammer is often perfect for this. A double sledge will also work well. Cut off what you don't want, then re-forge the working end to the desired shape. Done right, the eye will remain the same. Harden in oil and temper at 450. Make a nice handle that fits your hand and have at those sword an knife bevels.