Disney didn't cancel Frozen 3D just made it a Wal-Mart exclusive.
I just received this email from Disney (I had emailed them on 12/25).
"Thank you for your e-mail. We appreciate your interest and are happy to answer your questions.
We are sorry that we do not have any release details available for the 3D version of FROZEN at this time. We will forward your request to the rest of our team.
If you have any other questions or concerns, please feel free to reply to this email. You may also contact us at 1-800-723-4763 (Canada: 1-888-877-2843), Monday 9:30-7:30 and Tuesday through Friday 9:30-6:30 CST.
Walt Disney Studios Distribution Consumer Relations
US and Canada"