I agree with Henk also - we are using the exact same staging structure!
I know the discussion is "closed", but i really wanna stress that migration to AS 7 will be a *huge* project for us if the "old", "wrong" deployment of various resources such as datasource, mail-services and jaas configuration inside EAR files, is discontinued. It will be like 40+ JBoss 7's that must be configured. For us, it is a huge advantage to have as much configuration done "at home" as we then control everything and have everything under version control.
Maybe we are doing it wrong, but for me it seems that the cost of doing it right is very high. Please reconsider some kind of backwards compatibility!