My MarkDown search has led to one more possibility, until I can port or develop a more full-featured “Byword” type editor. It’s called TextMate, and it’s pretty decent.
If you need a good free text editor for coding projects, you can’t go wrong with TextWrangler as I suggest on this site. But TextMate is another great option, except that it is shareware. You can still purchase a license for it, maybe even get one free if you work in the academic field. I ended up with a license from an old MacHeist contest sometime ago, so I was excited to be able to give it another go.
The good news is that when you download version 1.5.10 for Tiger or Leopard, it comes with a MarkDown bundle pre-installed. As you write your MarkDown, you can pull up a nifty preview window with a few different styling options to see how your writing looks. You can then export it to html or possibly use other TextMate features to send it to a blogging engine of choice.
There appears to be a newer version of the MarkDown bundle, but I am guessing it is only compatible for the newer beta version of TextMate, which is intel only. However, we at least have two legitimate options for writing using MarkDown for the time being. That’s better than nothing.
My mythical search is really for something more like Byword, less a text editor and more of a distraction free writing tool. Stay tuned.