Something

def my_blenderbuilder(target, source, env):
	print "Hei!"
	return 0

def my_blenderbuilder_print(target, source, env):
	print "Hoi"
	return "I should build '%s' from '%s'" % (target[0], source[0])

myaction = Action(my_blenderbuilder, strfunction=my_blenderbuilder_print)
mybuilder = Builder(action=myaction,
						suffix = '.zzz',
						src_builder = ['CFile', 'CXXFile'],
						src_suffix = '.xxx')


env['BUILDERS']['BlenderXXX'] = mybuilder

xxx = env.BlenderXXX(target='test.zzz', source='test.xxx')
Default(xxx)