Wow! Unfortunately, I know Java not. But it should need a couple of things: a randomisation function (it's only one cloud all the time), an export image module and an ability to change resolution to at least 1024x1024. Not to mention a GUI. That would be a very useful app not only for Bryce but for other programs as well. Even Photoshop. And it could use the PNG format with transparency in order to avoid various copyright things. Ever thought about contacting Perlin himself? Or people at sourceforge?

-- erlik