This is more of a question since I don't know how to enter in contact with you guys :-)
Why am I contacting you?
I've seen J C's talk at JSCONF.EU and I've read the MANIFESTO and as far as I can tell, @seldaek did exactly what you want to do for JavaScript (an independant package manager) for PHP by creating composer.
Now composer is tied closely to packagist which is it's default package manager but composer's as well as packagist's source code are open source and although both licenses are hold by their initial creators, if someone was to create a freer and better version based on both of these things, this would not be a problem (as far as I unterstand their license policies).
Also, you are not required to publish purely PHP packages, so you could imagine publishing JS packages using composer too, so this could be something to start-off too.
I'm totally aware that you're not going to use composer as replacement for entropic, seeing how far you've already come and what your goals are, but I think that a look to the left and see what's going on at PHP and even contacting the people behind composer and packagist might help you make some quick decisions that you state as important in your manifest.
Finally
I hope I'm not stepping on anybody's toes by talking about PHP to JS developers trying to make a fair competitor to npm (and after J C's talk I know that this is needed and maybe banding together with the other Web communities is a solution to make the whole web stronger.
Is this a feature request or a bug?
This is more of a question since I don't know how to enter in contact with you guys :-)
Why am I contacting you?
I've seen J C's talk at JSCONF.EU and I've read the MANIFESTO and as far as I can tell, @seldaek did exactly what you want to do for JavaScript (an independant package manager) for PHP by creating composer. Now composer is tied closely to packagist which is it's default package manager but composer's as well as packagist's source code are open source and although both licenses are hold by their initial creators, if someone was to create a freer and better version based on both of these things, this would not be a problem (as far as I unterstand their license policies). Also, you are not required to publish purely PHP packages, so you could imagine publishing JS packages using composer too, so this could be something to start-off too. I'm totally aware that you're not going to use composer as replacement for entropic, seeing how far you've already come and what your goals are, but I think that a look to the left and see what's going on at PHP and even contacting the people behind composer and packagist might help you make some quick decisions that you state as important in your manifest.
Finally
I hope I'm not stepping on anybody's toes by talking about PHP to JS developers trying to make a fair competitor to npm (and after J C's talk I know that this is needed and maybe banding together with the other Web communities is a solution to make the whole web stronger.
Thanks for taking your time reading.
Best Regards Tizian