A product advertisement for movie 11 pens may have revealed the existence of an alternate form of Shaymin, though the evidence is based on correlation.
Giratina’s pen, as shown in the advertisement to the right, is gray on top and red on the bottom, and features a picture of itself hanging from the actual pen. In contrast, its alternate form is featured on another pen with the same colors, but reversed.
Shaymin’s pen is green on top and gray on bottom, while another pen, which is coincidentally placed right next to it, features the reverse coloring of Shaymin’s pen (gray on top, green on bottom). Could this mean Shaymin will have an alternate form in the movie as well (perhaps as “New Pokemon A” or “New Pokemon B”), since the second pen has its colors reversed like Giratina’s alternate form pen? Click the image to the right for a larger scan.