That is a solution, but it's a pain in the butt. An overhaul of the landing page designer is in order and I'd say adding webfonts would be part of that.
Love how Marketo makes it easy to whip up a landing page quickly but the result is that most Marketo landing pages...look like every other Marketo landing pages. Increased thought to UI and elements like the easy addition of Google Fonts and Web Fonts would go a long way.