Heave you recognised the development of the Suska IP core (ATARI STE+ clone)? I think they can also use some help with coding. Itīs an ongoing Project for 5 years now.
Maybe the Atari-platform is down because of all the people making their own small projects, like the ACP which is 1 or two peple the last 4 years.
Contact them, maybe it coulīd also be your project.