I have an SVG with some basic javascript interactivity, and I would love to be able to put some audio into it as well.
To clarify:
If you require a browser with support for HTML5 audio, then it's possible to just put the audio elements in the svg (use the XHTML namespace for the audio element and its children). Last time I tried it didn't require a foreignObject wrapper. Here's an example showing how to do that (works in chrome, firefox and opera).
It's also possible to create HTML5 audio elements with javascript and use them inside the SVG.