one thing you should wonder, do you think is good enough to leave a image to represent a heading? you might think, oh cool that look nice, but remember it affects SEO, there is another solutions for this workaround (cufon) but is not as flexible as webfonts, i think that webfonts will never replace a system font, but the web designers need to get a fallback, a reliable fallback.

Answering your question, i think is not possible to get the benefits from a webfont, but one possible solution for your problem related to the downsides is to ask the visitor to install the font required, but it would be not practical.