OK, after doing some serious reading here is my argument for allowing this, in the Core Rule book starting on page 140 is the heading "weapons" that lists, well, weapons, and under that heading is improvised weapons. And according to masterwork weapons even if you plan on using using something such as a shield as a weapon you cannot get the enhancement bonus to attacks, and as shield bash (on page 152) says a shield "can be made into a magic weapon in its own right". This does seem to indicate that items, even if they are not "weapons" could be enchanted as weapons.
So in short I'd say that a masterwork crowbar would not give an enhancement bonus to attacks but could be still enchanted as a magic weapon.
Any thoughts on this?
