I'm in the process of upgrading to Rails 2.1 and refactoring El Dorado a bit as I go along. I expect to start in on the blog feature this month, but I wouldn't expect anything feature complete until late July due to my upcoming traveling schedule. Once the blog is all finished up, I'll get into theme support, but I'm not sure how long that will take.
I don't have any plans to integrate any external apps into El Dorado at this time, and integrating a PHP app like WordPress doesn't sound at all like something I'd want to try to tackle. The reason I started working on El Dorado in the first place was because I found it too difficult to try and integrate even two WordPress apps into a unified site.