That's a slight markup...

The seller has some nice pieces, but I can't help but feel he is spreading some major misinformation. He has a couple Jeremy Bastian pages and in the description says Jeremy doesn't sell original pages (might be true) or commissions (the two times I saw him this year at conventions he was taking commissions, in fact, I got one, so that's not true). Ergo, when he says Usagi has an upcoming standalone movie and is rumored to feature in the new TMNT movie, I wonder how much of that he's just making up.
A third TMNT movie has not even been announced, so it's way to early to know what it would even be about or who it would feature. I don't feel like Usagi would translate well to a live-action movie anyway (even if he is CG like Bebop and Rocksteady) and the quality of the new movies, in my opinion, is not worthy of having Usagi as a character, so I have practically zero interest in seeing him in a potential TMNT 3 unless a completely new creative team is brought on board to take the franchise in a whole new direction.
I'd love to see an Usagi stand alone movie (classically animated, CGI, or stop motion), and there was some development on a stop-motion version a while back (which produced a short proof of concept), but last I heard they hadn't found the necessary funding to turn it into a full feature length film. Perhaps with David Petersen's
Mouse Guard getting the feature film treatment, maybe there will be interest in other animal-based, comic book derived movies. But if enough time goes by without an Usagi movie, maybe I'll eventually get to the point where I can get it made.

I have a list of feature film ideas that I'd like to direct and an Usagi Yojimbo movie is in my top 10, maybe even in my top 5, projects I'd want to do.
What we do know from the leaked Nickelodeon pictures is that Usagi appears to be getting an action figure in the TMNT lineup. We also know he's set to appear in some capacity in the TMNT cartoon. That's all I can say on those, as that's what's been publicly announced/leaked so far.