I've got a number of Mew Mystery Gift codes set to expire tonight.
I've had them for a bit while I debated on selling them, but decided against it entirely as it was just a little too scummy for me as a huge Pokemon fan. Since they expire today, that should prevent any sort of reselling by anyone less scrupulous than I.
tl;dr If you want a Mew code for any of the 4 3DS games, post in this thread and I will PM you one (possibly more, if there's not enough interest). I've got plenty, so don't be shy.
Edit: Remember, these need to be used by tonight.