I tried getting codexers in for a Cockatrice tournament once, but there was literally zero interest.
It's usually difficult to talk people into being first at everything. We do seem to have enough people around who (used to) play it, plus some of them may have pseudocodexian buddies they can bring along as well. (A practice we should henceforth refer to as Juuling).
If someone were to hypothetically get things underway, I think this is how he/she could go about it.
Step 1: Get people interested in/aware of MTG via cockatrice. Play a game or two via cockatrice, post AAR here or in the playground. That'd give people a feel for how the client works and interested in trying it.
Step 2: If the AAR genereates alittle interest, write up a handy how-to tutorial with pretty pictures on how to get cockatrice, where to download pictures of cards (borderline piracy? I'm not sure how to interpret the KKKodex rules on this), install stuff, build a deck, connect to a game etc. Extra points if you can talk a group of people into making a Kodex Kard Klub thing a la CDS where people signal that they'd be up for game(s).
Step 3: Once there's a small core of users willing to play, agree on rules (which sets of cards, whatever else... not sure what kinds of things you'd need rules for. Possibly that people need to use the same deck for every game and submit them ahead of time?) and crosspost a recruitment thread here/in the playground. If someone gets the ball rolling, I'll sticky a recruitment/tournament thread in the Gazebo for the duration of the event.
Step 4: Bang your head against the desk in fustration when clusterfucks, dropouts and butthurt inevitably arises
Again, I don't mind helping with arranging things if someone else can determine what needs to be done. Unfortunately my knowledge of the MTG rules is minimal, so I'm ill prepared to sort through the pitfalls on my own.