Now that the double-deck exists I think this is well worth a run-out, with each player receiving a full Decktet (minus aces, crowns, and the extended deck cards) and playing in the usual way. I think this would lead to more manipulation of the jury, and I think it also lets games, potentially, play out very differently: do we fight aggressively over every card that's put into play, or do we take a laid-back approach since there will be time, with the surfeit of cards, to get your own cards in play later on.
I've also been thinking about whether this could be a non-Decktet game, sort of like how Sorcerous Futures became Speculation. Just mapping the Decktet onto a thematically-appropriate deck seems a bit lame, but (fortuitously?) it also seems quite problematic. What are these six suits that the jury members each individually care about and that each card has two of? Since you're playing them as part of your case, I thought it would be things like "physical evidence", "eyewitness testimony", etc. But what exactly does it mean that a card is both "physical evidence" and "eyewitness testimony"? As an abstraction it's fine, but to make this a concrete thing, like "Vinnie the Stool Pigeon" or "Bullet Casings" or whatever just seems weird.
But perhaps a different approach is to have the suits become two sets of three: the three principal suits, "motive, means, and opportunity", and the three supporting suits, "physical evidence, testimony, and documents" (or whatever). Thus a card is always part of two suits, but it's always one principal and one supporting suit.
The deck that would result from this would be different, structurally, from the Decktet, but in principle it seems like the same game mechanics would work.
In addition it could mean that there could be some sort of overall bonus if you win two-out-of-three of the principal suits, or perhaps this is the tiebreaker.