I know this is a total hack but thought I should add this sample open source audio library I put on github awhile ago...
https://github.com/run-time/jThump
After clicking the link below, type on the home row keys to play a blues riff (also type multiple keys at the same time etc.)
Sample using jThump library >> http://davealger.com/apps/jthump/
It basically works by making invisible <iframe>
elements that load a page that plays a sound onReady().
This is certainly not ideal but you could +1 this solution based on creativity alone (and the fact that it is open source and works in any browser that I've tried it on) I hope this gives someone else searching some ideas at least.
:)