Yes, non-static patches such as thcrap are supported; in fact, they are recommend over static patches.
You can do so by going to your installation folder and placing the image (160x60 PNG files) into the folder named 'images' with the file being named as the default file in the folder and 'random' for the random button.
Inside the Launcher's folder, inside the folder named 'langs', use whichever file as reference, remember to not change values' keys (the part before a semicolon), and to change the 'title' to your language's name and 'code' to your language's code (i.e.: en-GB, etc.).