thank you for your interest. There was a plan to implement this feature, but because of a lack of time we haven't got to it yet.
If you want, you can help us with it - we would be more than greatfull. As an inspiration you can take a look at two current extensions - for Browserstack and Saucelabs: arquillian-extension-drone/extension at master · arquillian/arquillian-extension-drone · GitHub
or any other current implementation of WebDriver factory classes: arquillian-extension-drone/drone-webdriver/src/main/java/org/jboss/arquillian/drone/webdriver/factory at master · arquil…
If you are about to start coding, please just let us know on this forum or here: Add support for Appium · Issue #86 · arquillian/arquillian-extension-drone · GitHub
If you have any questions/corncerns, don't hesitate to ask.
Thanks for the update!
Since we need Appium pretty badly I'm going to develop the Arquillian extension.
Awesome! Thanks for getting involved. If you need any help just ping us.