As mythic rares, these cards are going to be difficult to pack anyway, but these variants are likely to be highly sought after once the set launches, not just for the value a complete set of the elder dragon cards may hold, but also for their eligibility as Commanders
The problem, for a long time, was that the alternate cost of sacrificing three creatures was actually a benefit, creating multiple Zombies via Bridge from Below
I didn't have G-Booster, so I used G-Scope as my ACE SPEC (and I still used Cheren in my deck)
Finally, at the end of the turn, you put the reanimated creature into your hand and the cheated creature into your graveyard
This is definitely a good possibility as, going forward, there will be three Universes Beyond sets per year (also mentioned in Rosewater's blog)