We were supposed to be getting a crossover comic this month, which might be delayed for a while, between Transformers and My Little Pony, but word from a MLP fansite is that there will be a "Crossover Collection" toyline of Ponies that feature decos and accessories homaging other classic Brands - Ghostbusters, Power Rangers, Dungeons & Dragons, and of course, Transformers.
These are the sort of wacky things you'd see as SDCC exclusives, but it looks like this could be a proper retail toyline for MLP.

Official information and images are limited at this stage, but so far there looks to be a number of single packs and at least one 5-pack.

Single packs -
Ghostbusters - Plasmane
Transformers - My Little Prime (could it look a little like the one on the front of the 2013 convention comic?)
MMPR - Morphin Pink Pony

5-pack -
D&D - (names not yet known) A Wizard, Druid, Barbarian, Rogue and a Bard.

As soon as we get images or official info of the Transformers Pony, we'll post them up here.