The first release of jbossbuild is complete. While there is no released distribution as such, you can try out the new build system by following the directions at:
+ Ability to download 3rd party libraries from online build repository
+ Builds a runnable incomplete distrubtion of JBossAS
+ Enables declarative builds
+ Enforces build uniformity
This includes a tutorial on creating a component build, as well as adding a 3rd party component to the repository.