This is about all else I can see atm.. The picture above was posted on the Forza facebook page with no other details.
http://www.theverge.com/2015/1/12/7533693/forza-motorsport-6-ford-gt-naias-2015
Just hope they don't rush this one and pick things back up like in FM4. Looks like they may finally have some competition with project cars too.