There is the journal module which is a blog. It has the basic feature of a blog. The web interface stinks. So you are welcome to do this one, you can either start from scratch or improve the existing journal.
For the RSS, there is support in Nukes for RSS, there is just a need to connect a module to the module. There is an example of how it is done in the news module which exports news as RSS.
Iff you want create a new module, provide the code, I will import it (I prefer this method rather than, adding everything, it's neater) and will give you RW access to the CVS. It does not need to be complete but at least I need the build structure (build files, src/main, src/resources, etc...). If you want improve the journal module, I will give you RW access too.