I heard of something call UICompiler I am trying maybe you would like it. Here is a link
http://uic.sourceforge.net It looks good, but I think it uses Swing, but you can make swing look really good if you want, here are some articles that might help
http://today.java.net/pub/au/79 Hope it works well. Also I heard of a Visual Editor for eclipse, but couldn't get it to work.