Here's a trick to get around the black title screen and jump into the game. This works great on my Linux Mint 12 running CrossOver 11.2.1 on x64.
The trick is to enter the necessary information blindly. It may be useful to search the Internet for an image of the GW2 title screen to use as a reference.
After installing GW2, start the game. Wait for the black title screen to come up.
Once the black window is up, hover the mouse around the mid-upper left area. The point should change to an I-beam when over a text field such as the email or password. Locate the email field this way. It's above the password.
The next series of steps are going to be completely blind and may require more than one try. If you muck up, just quit the bottle and try again.
When you have determined the location of the email field, click in it. then enter your email. Afterwards, hit the TAB key and enter your password. Once done, hit ENTER. The game should start!
Remember that the above steps are done completely blind. I mucked up the first try, but on the second try, the character selection screen popped-up right away. I was so surprised that it actually took me a moment to realize that the game had started (yay!).
If you are feeling adventurous, consider tabbing through the options to remember your username and password and login automatically. In my case, I can start GW2 straight from the KDE Launcher and land in the game.
If you get your game working, come and say hello to Sora Realmweaver in GW2 ;).
