No, it wasn't a video (I shun videos), but I'm reading through /r/Tulpas and apparently they acknowledge it's a really common thing for tulpa-enthusiasts ('tulpists'? is there a word for them yet?) to make ponies: http://www.reddit.com/r/Tulpas/comments/14zbli/the_internet_is_laughing_at_us_and_you_shouldnt/c7hy6mk So I guess it could have been any of a lot of people.

EDIT: I find the religious connection very interesting since it reminds me of the Christian practices I've read about before, so I've asked them about it: http://www.reddit.com/r/Tulpas/comments/1e33z2/comparison_with_charismatic_christian_practices/