Both the c200V2 and the E200V2 seem to use different hardware and as such will not work with the current C200 and E200/E200R builds.
Support for these will require a completely new version of Rockbox, and will require complete reverse engineering of the product again.
If enough interest is generated, and enough information can be gathered on the original firmware and chipset, it may happen. But seeing that Rockbox is a volunteer effort, it seems that most of the work is done by people who already have the players and want to Rockbox them.
You can contact the Rockbox team and see what you can provide in the effort to help port it over. That may include disassembly of the unit with clear digital photos of the internals, or helping in the programming effort.
I'm not saying it WON'T ever be done, but the interest and information gathered has to reach a sort of "critical mass" for it to move forward. There is still no support for I-Pod 2nd Gen Nano's as their original firmware is tightly encrypted and there has been no way to un-encrypt it to start on the reverse engineering process.
The V2 Sansa's may have the same issue.