I am working on this goal now.

I think including a messanger is a bad idea. Users should
trade addresses for an otr-XMPP chat, to securely talk
about illegal activities.

https://github.com/zack-bitcoin/NewsCoin

It has a built-in reputation system, and NxM addresses
for easy escrows of all types.

It uses Slasher instead of POW. Miners have an incentive
to do networking so that they can collect transaction
fees.