Rockbox is Linux. There are several documents and tools how to start developement for a new player. It takes some time to find them all on the rockbox page. So, let's slow down and read that stuff first.
The critical point is the bootloader, which let you choose between original FW and rockbox. If you build a bootloader and it doesn't work, than you got a problem. I don't know how to get back to virgine state.
It's not a good idea to ask rockbox developers for a new port. It's explicitely writen on their page NOT TO DO THAT. They may help you after you startet your own project and you got a special question.
If some guys got guts and want to risk to break their player by a bad bootloader, than we could start developement. I got the tools, but at the moment I don't risk to break my player, because there is still warranty.