I just downloaded and installed the qemacs editor. (Debian: apt-get install qemacs.) If you open an HTML file with it, it renders it and lets you edit the rendered version a bit. You can get at the source for more serious changes with M-x xml-mode, but it surprised me that a sub-200k editor contains an CSS-based HTML renderer. Amazing, eh?

It also can edit utf-8 (multilingual) with a variety of input methods taken from Yudit. It's still early days for this editor (and I've filed some bugs against it), but it's quite promising and I thought I'd let you all know.

QEmacs is at http://fabrice.bellard.free.fr/qemacs/ Yudit is at http://www.yudit.org/