
As Danno notes, the foundations of Griffon were laid over a year ago, at the time when SwingBuilder made the switch from Java source to Groovy source. A bit later after that FactoryBuilderSupport was born, and its thanks to FBS' extensibility power that another piece of the puzzle was created: the CompositeBuilder. This key component of the Griffon project allows you to mix&match any FBS based builder (like SwingXBuilder, JideBuilder and GraphicsBuilder) into a single cohesive unit, or a modularized one as it supports a variation of namespaces, which means that a set of factories may have a prefix to distinguish them from other similarly named factories contributed by another builder.
Enough on the background story, are you still reading this?! go download Griffon and take it for a spin!

[Download|Install Guide|Quick Start Guide]
Let Griffon take your Swing application development to new heights

Keep on Groovying!
PS: use jdk6 for better results (like speedy Swing, Nimbus L&F and other goodies available only in j6u10)