Yeah, I had, but it didn't go into how to lay out the project so that you could invoke the standalone runner and have it pick up the plugin classes from eclipse's build output directory. As it happens, it doesn't seem to be possible; Hyperic only seems to work if you have the plugin in a jar file, so I've modified the Eclipse build to use an ant file to write the plugin jar before invoking the standalone test tool.
It's a bit of a set of hoops, but it all works out in the end.