https://tomverbeure.github.io/rtl/2018/12/06/The-VexRiscV-CP...
https://www.oracle.com/servers/technologies/opensparc-overvi...
https://opencores.org/projects?expanded=Processor
I agree that manufacturing is a real problem. FOSS processors can get adoption but until we open up the manufacturing pipeline they won't provide end users with the benefits we get from FOSS software.