Application Server Independent Installer

We spend too much of our time customising our Ant-based installation program to support multiple application servers. Our installer does the same things on different app servers:

• Deploy some WARS & EARs
  
• Setup users
• Setup Datasources
• Tinker with class-loading
  

However it must use different mechanisms for each app server which is what causes us the pain. Are we the only ones in multi-app server support hell or is there a market for an installer which abstracts up from the app server?