I don't feel good about giving advice on this topic, due to the eBay thing. But, this is an information sharing forum and maybe information like this could be useful for others for some other purpose.
If you knew the dimensions of a 1/10 gram "bar" , length, width, height. ( sorry not going to do the math for you ). Couldn't you just make a two piece graphite mould with a long thin cavity. Same width and thickness of the final product but longer so that you could then just cut it into several " bars" . For something that thin you might have to use a centrifuge type moulding device like a jeweler might use to cast a ring or earring.
Seems like a lot of work to me though, and based on others comments, a lot of headaches! But maybe that's just me.