I wonder, outside of a few ice fishermen, how many molds would have to sell to make creating a mold for this jig profitable? Then those flat eye hooks would have to be available in very small sizes. The design or shape of the jig might lead to casting issues when the break-off for the sprue is considered. I could see a rtv rubber mold for this jig style being done for spin casting as the break-off would be clean and flash at that point minimal, but I think a conventional mold would have issues.
As for the tungsten powder, it is available but by pouring some in a cavity and pouring in lead, the lead would float on the powder and not incorporate with it. Resin/tungsten could be done to make a paste and I have looked at doing something on this order. A couple ideas that came to mind were 1. to make a paste and fill each side of the molds cavities with it with one side a little high so that when the mold was closed the two sides of the paste would meet and fuse as the resin set and, 2. make a looser resin/powder mixture that could be poured into the gates with a spoon or small ladle. I was really leaning towards the first option until I saw how much a couple ounces of the tungsten powder would set me back just the play with the ideas. And then the resin would mean a no-heat paint job.
The popularity of the original Diamond jig brought out a ton of pirated copies, hence the wide spread availability by seemingly everyone who makes tackle. I think within a year or two these jigs will be all over the place as unfinished heads and will be too cheap to mess with a mold. Then all a guy will have to do is figure out how to get them gold plated cheaply.