The MOSS Feaure Generator is very well suited to be used with the WSPBuilder. One using both in a combination, you can get from zero to solution packaged feature in minutes. All you need to do is generate the features in the directorystructure required bij WSPBuilder. You can find both at CodePlex:
http://www.codeplex.com/wspbuilder
http://www.codeplex.com/mossfeaturegenerator
Alfred
weerda