Not only is Green all about artifacts, fliers, and land destruction, it also has a "Golems matter" theme!
Now I need to build a cube where Greenie Weenie is a theme. It showed promise here, but is not quite bizarre enough.

New identity for Green! Artifacts matter!

Some big changes coming, but here are a few more quick swaps in non-green colors.

I don't expect to find additions to this cube often, but here they are! Phoenix of Ash was too aggressive for red, and I love the enemy color requirements for Firestorm.
Also, Stalker may not have done much in DMU limited, but it should fit right in here.

For a card printed very recently (as of this posting), Emerald Dragon sure does a good job of slotting into this cube of cards that don't quite feel right.
Vorpal Sword played into black's affinity for equipment/artifacts and offered another route to victory, but it felt too much like a conventional black card.
Likewise, ambusher continues to emphasize lifegain, but also artifacts.

Red needs a slight nerf

New achievement to unlock in this cube - play a red rummage spell with flashback. Flash it back, and then use "Search for Survivors" for a guaranteed reanimation.

I decided to double down on Rebels so that black isn't pulled in too many directions. It's general theme is "small guys working as a team". Now black's themes are lifelink, exhalted, and rebels, which definitely feels more (in)appropriate.
I still need to swap out a few artifacts, but I am keeping the "black is best with artifacts" theme going too.