yes we used Byteman for similar things, but it seemed overkill here as really I was just verifying the user report.

What I meant is that we could have an "in-memory" appender for JBoss Logger: would make tests quicker as it won't write to disk, and allow some kind of static lookup to grab a reference to the last N lines in the buffer.
A bit more complex to write, but I guess it would be highly reusable across projects? Just an idea.