Fifth generation homebrew?

[Manhattan Sports Club]

I am interested in seeing fifth generation homebrew, not some media-player or emulation wankery but actual homebrew releases. However, I understand this is more difficult than your standard cartridge based system due to special disc and protection measures used. I am wondering if it has already been considered, and what can we do to address the issue to allow the possibility of commercial homebrew releases that would not require a mod chip?