Sorry for the very delayed reply - been busy in the foundry.
Here's what you need to do. Get some wax and sculpt it into the neccesary form by any means possible to you. Fortunately, wax is extremely easy to carve, weld, melt, cast, bent, soften in warm water, etc.
If you dont have a foundry at your disposal, and most people dont, just get some clay slip which is ordinarily used in ceramics and dip your wax parts in the slip and let it harden. Hopefully it wont crack. In India they usually paint the wax with alumina as a first coat - it's painted on. Then they build up thicker layers of material. You might be able to splatter your parts to build up a thick coat without cracking.
Wax is very easy to weld with a soldering gun. This thing will need sprues and runners and risers etc, then just burn out the wax in a hot furnace and pour in the metal.
The most expensive part of this process if the SAFETY EQUIPMENT which you will definately need if you value your eyesight.
I am actually working on some connectors like this at this very moment - but they are not cubic vertices. The connectors I'm making are for making an icosahedron, and other similar things.