On Rober L. Read's blog I found that two people participated in Esperanto. Unfortunately, the links that he link to are dead. I imagine that they would be the evidence we're looking for.

I found this, too: Goulo's livejournal.

Other than that, this person on tumblr seems to have participated: Pretervola alhxemisto.

And we'll see what comes out of this: gerogeropyo - this person is planning to participate this year! Good luck! Update 2019: Unfortunately, this Wordpress page has been deleted.

And this person that also blogs about Esperanto participated successfully in English in 2013: Arion's home. Maybe we'll see something in Esperanto one day? :-)