I really don't there's a need for a special application for this; I use Emacs's markdown-mode, python-markdown, and xhtml2pdf along with a docview pane to edit and preview Markdown, and I can't imagine a smoother experience with a dedicated editor — plus I get to use the editor to which I'm generally accustomed.
You're right, you definitely don't need a dedicated application, but I would rather just open up one executable instead of cobbling together multiple utilities. It's all about your workflow though, for me, I feel more comfortable using a M↓ where scrolling is synced and it can watch what I'm doing in real-time.
I'm gonna look into your setup though. I'm definitely all about being on the terminal, does your setup work well with VIM as well?
Not really, since it relies on Emacs' docview mode, which can display the pages of a pdf file; I'm not aware of a way of doing that with vim. If I were doing it in the terminal, I'd probably use w3m in Emacs to roughly render the HTML. I don't know if that's possible in vim either, but it seems more likely.
