You are wrong about Sake I think.
I know Sake. I've written a generator for builder.seaside.st. The result (or a modified version of it) is included with the Sake distribution as Seaside29Builder.
Sake can declare a universe of known-to-work-together packages. Just take a class, declare the sake tasks you know work together in the image you target and things will be as in universe.
Sure, you can use Sake to build something very similar to a Universe. However tasks are not declarative, but instead use a script to perform some actions. In most cases they call Installer to find and load an appropriate version (what is already scary in itself). I understand that Package Universe is too restrictive for some cases, however I wouldn't dare to replace it with Sake. Sake depends on a stack of hacks, it even uses its own compiler to allow uppercase method names. In the small codebase Code Critics finds 14 serious bugs like non existing inst-variable references and message sents that are not implemented anywhere. Of course there is not a single test. The way Sake calculates dependencies is totally strange, I am not sure if it is even correct. Lukas -- Lukas Renggli http://www.lukas-renggli.ch