Another option is lithographs from IDW limited.

There's a couple of 18"x24" lithographs for $25 each, or there's smaller ones as part of their comic folio range. I think they have plans to release more over time, as well. Lithographs are a much higher quality print than posters and will look fantastic in a frame.

Might be worth checking out bluedogposters.com.au or allposters.com.au as well. Mostly Bay movie stuff but I did see a TF Animated one and one for the '86 movie on allposters.

Quote Originally Posted by Griffin
There are a handful on ebay...
I like the description on some of those:
Artists of the poster is famous Transformers Artist Pat Lee!
By all accounts that should probably be infamous.