This is going to sound like something you may not like, but I was thinking: what would it be like if the ponies went into the world of Littlest Pet Shop, and vice versa? I think that would be a pretty cool thing, but if the ponies did go into the LPS world, people would wonder what kind of animal they would be. Would they still be tiny ponies or another animal, or would they turn into humans? (EG doesn't count as they are humanoids, not 100% human.)
Also, if the pets and their guardian, Blythe Baxter, did go into the pony world, would she turn into a pony and the pets stay as pets, or would the pets turn into ponies as well?
Whichever one of these happens, what would they do? How would they find a way home? What fun would they have, and who will befriend one another?
Anyways, those are only my thoughts. What do you think? (Yes, this is quite short because I didn't put much thought into this one.)