Troll druids are a new Horde race/class combination coming in 4.0.3a. As of 11/20/2010 – The troll race has unique forms for cat, bear, tree, & moonkin on Beta. However, trolls are currently sharing Tauren’s flight form (though we have seen previews of what the troll epic flight form may look like in the future). They are also using the old travel form & swim form models.
Here is the Troll moonkin form. It is a re-color of the Night elf model.
Here is the troll tree form. This is active when you use the tree form cooldown. It is also possible to pick up a glyph to get the old treant form instead of this new tree, if you don’t like it. It is NOT currently possible to look like a tree when your ability is on cooldown.
The troll cat & bear forms depend on the troll’s hair color. The hair colors are the same for male & female trolls. Below are the matching for hair color & form combos. I have the male & female hair, just for verification that they pair up the same for the trolls, along with the cat and bear form that matches each color. I split it into 2 charts, just for ease of construction. I will likely update these later with slightly better copying & pasting skills, but the color basics hold regardless. For another look at how they pair, you can see a chart on the mmo-champion forums.
For the troll flight form, it is CURRENTLY the same as the Tauren. Here is the mmo-champion preview of what troll flight form will likely look like in the future.