Heya...
There probably isn't going to be one for the foreseeable future.
We'd need:
1) Someone with time to write it
- or -
2) Ability to update the core code to an updated version which does have a built in mobile target. But all the Dokuga code would need to be updated for this new version.
I quickly tested route 2 years ago. Base site functionality existed on update, but most of the core fan fiction code was broken and would have needed rewritten.
So yeah... it really comes down with the time to actually get something done which just doesn't exist right now.
-M