James Clarke turned me on to the fact that modifying the Expression Encoder templates is trivial. I tweaked the AudioGrey template to turn off autoplay and changed the default volume. Of course, one could even take this further and really modify the templates, which Tim Heuer has a great post on. So, this makes for a streamlined workflow for getting audio (or video) onto your blog. The pieces of the puzzle:
Expression Encoder
Silverlight Streaming Publishing Plug-in
Silverlight Streaming Account
Windows Live Writer
Silverlight Streaming Live Writer Plug-in
The net result: here's the audio player playing my composition hill.climb embedded in this blog post: