i've built beet so far mostly on my own. If you want advice on how to use it, you can ask me (you are clever; i'm sure you can figure out how to get in touch).
Also, i built beet at the request of dtek. They've given really good advice on what the expected behavior should be, and have a firm grasp on how to use system. They're busy folks, though; you might have better luck getting their attention if you have a potential job for them.
If you want to modify beet yourself, you are of course welcome to do so. You can find a published arch mirror for the project here. If you have a change you want made, you might consider hiring me to make the change. You might also consider looking at the to-do list to see if i've thought about your issue already.