With the current state of affairs, I would go with the TeX -> image route, with a utility like
tex2im. To make your life easier, you could include the TeX code in the HTML, either in an "alt" attribute or as a comment, and have a script automatically process all the needed formulas and generate the images. something like this:
HTML file:
Code:
<p>A nice identity:</p>
<img class="TeX" src="formula1.png" alt="e^{ix}=-1" />
and then have a script look for <img> elements with class="TeX", generate a temporary .tex file with the "alt" content, and run tex2im to create the file named in "src".
This script seems to use a similar idea.