-Why has nobody dumped the card?
The only people who can do that are Japanese players who bought corocoro. There aren't that many of those who are interested in doing that on english sites.
-Is that something currently not supported?
No, it's trivial to dump a card, but we don't know of anybody who actually has it. (Only people who redeemed a code for the card can dump it. People who received the ticket via pass CANNOT).
-Can't we just create the wondercard?
No, the game checks for an unknown flag in the wondercard or for a specific WCID or something. We don't know what it checks for, and the search space is too large to feasibly brute force. Making a normal wondercard that gives an eon ticket doesn't work.