I'm sure it is possible to get the base system of WebOS working on the tablets with the list of opensource packages provided by palm, but the more important and major issue is the fact that the mojo framework which drives most of WebOS's user interface is proprietary, meaning that the only way to actually use WebOS' UI or the applications provided is to either get special permission from palm, which i highly doubt would happen, or create an opensource mojo clone. I think the big issue right now is how to legally bypass palm's mojo framework.