The "font-variant: small-caps" property doesn't actually map to the small caps, instead the browser scales the uppercase. The obvious solution for web fonts is keeping the small caps in a separate font file (sc instead of the lc). This causes a problem: someone using a browser that doesn't support @font-face will see lowercase characters where you intended uppercase characters. How would you solve it?
Another issue: I'm thinking about building a font with a set of ornaments for a web site project. A less updated user might end up with a system font instead, leaving the ornaments useless. One option might be using Wingdings or Webdings as fallbacks, but that restricts me to their character set. I'm not really sure how "web safe" those are anyway. Do I have other options?