Thanks for this, J.
I hope my addled memory hasn't given you false hopes, but if there was any truth to what we were discussing in those earlier conversations I'd be so fricking stoked. Even if they wouldn't bother with a Derpy plushie I'd happily buy the others, especially if they came in gift sets and boxes.
No, I really do remember we had a conversation, and that I had learned from an email from someone that Hasbro was talking about making G4 MLP:FiM plushes. Hopefully, a rep will be able to clear it all up.
Now, that said, I do have a friend over at Brony Kingdom who has a friend who makes plushies. They're not intricately detailed, and they're not very big, but they're nice, certainly adorable, and I've been wanting to get one. She sells them for $33 a piece, which includes shipping. Her website is here: http://sodas-shop.tumblr.com/