That format has infinite mana of any type, but is limited to just one spell per turn, barring an alternate cost being paid like Force of Will
The ramp decks are easily built from main cube cards however the elf deck uses a couple of much more niche cards you rarely see in non-tribal drafting cubes
I took it apart for parts a couple of weeks back, and when looking for new Temur commanders printed this year, was dismayed to find that Miirym was ituntil the Tyranid Swarm is available
Since all the combos require my commander to instantly win, a quick n' easy way to do this would be just to swap Niv-Mizzet, Parun out with a noncombo commander and call it a day: Niv-Mizzet, Dracogenius is a straightforward swap if you still want to keep The Firemind in your command zone, or you can switch to another Spellslinger commander like Kaza, Roil Chaser
Faking magic cards is both easier and more profitable per unit than faking e.g