Was looking for this same thing 3 hours ago and stumbled upon:
SUI_Bulletin_Board + SUI_Message_Board (2 diff things) - they are $99 each - not sure if they use plugins (have emailed them regarding that) - sure they are not free - but they look the part. I am sure that you can do the same thing with some time/knowledge but $99 is not a lot.
I don't have any association with these things btw - they may be what you are looking for.
Just trying to help.
Got a reply - their solutions don't use plugins - am buying on Tuesday because I have a particular need and will advise if you want.
(I don't mind plugins - just that I try to minimise them where poss.)
As mentioned - grabbed 2 titles from SUI - both do what they say on the tin - pretty clean examples - should not be too hard to integrate into a solution. As a low level developer myself - you prob could do something similar yourself but for $99 - cheap solution and it works.