Here's a little one I made, most of the typical luthier's hammers you buy are within the 8-9oz range, I needed something VERY light that could be used to tap apart stubborn wooden guitar/violin pieces without applying too much force or denting the instrument. This is a stupidly simple design but it works for what I need. Made from ash scrap and oak.
I don't know if it actually weighs a 1/4oz but it's almost weightless in the hand.