A list of proposed CMB Science white papers can be found here: CMB Decadal Panel White Paper Wiki
The CMB Decadal Panel White Paper wiki was created to have a comprehensive view of science white paper activity, making it easier for contributors to join existing efforts, and also allowing us to spot gaps and work to fill them.
Anyone interested in joining a Decadal Science White Paper listed on wiki should contact the leader noted to volunteer to join the effort and edit the wiki page accordingly. Community members who wish to share their own Science White Papers with the community are also welcome to directly edit the wiki.