A good starting point for a new Ploneboard might be collective.ploneboard:
We did a Google Summer of Code project a few years ago but the student was not able to deliver a fully functional product.
For an experienced Plone developer or company it shouldn’t be a problem to build and release something in a fair amount of time.
I’d love to see this to happen. If there is anything I can do to help, let me know (I am the author of p.a.discussion and I was the mentor for c.ploneboard).
We might have the basic requirements documents still laying around somewhere. If someone is interested I could try to look them up. We could try to define what we need and then see if we can chip in to build something together…