I made some drawings of Ghost Trick characters as ponies many months ago and I was too lazy to add backgrounds until now. :'D
I'm pretty sure such a crossover has been done several times by now (if only I'd added backgrounds earlier).
Just about everything has been ponified, but it was still fun to draw.
I know ponies don't have to wear clothes, but drawing on clothes was much more fun!
I seem to have a tendency to draw things WAY too big on a digital canvas (ironically, the exact opposite problem that I have on a traditional canvas). Sissel pony gave me SUCH. A. HARD TIME. I actually went through two failed drafts before this one (which still could be better), you can see them here: [link]
After those, I had all sorts of troubles with anatomy, highlights, the clothes, Sissel's glasses, and the horn flame. At last it looked decent, although I'm still not completely happy with it.
Other Ghost Trick ponies: [link] [link]