Ok looks like it might take some work as the ouput still needs editing. However that should just be a bit of regex magic. So far this seems to work though in a basic not w3c kind of way.

(defun blog-region-html(beg end)
  "htmlize the region then blog it"
  (interactive "r")
  (setq htmlize-output-type "font")
  (set-buffer (htmlize-region beg end))
  (blog-buffer)
  (setq htmlize-output-type "css")
  (kill-buffer)
)