Without further ado, I declare that the new deadline is set to April 27, 2013. This gives you 2 weeks to finish your shrine and submit it. The original post has also been updated to reflect this change.
That's all for now :) Don't hesitate to get in touch if you have any questions or doubts.
P.S. To those who haven't messaged me back yet: could you please let me know if you are still interested in taking part of the marathon or not? Thank you!