<p>I know RIM has their own IDE (<a href="http://na.blackberry.com/eng/developers/downloads/jde.jsp" rel="nofollow noreferrer">BlackBerry JDE</a>) for building BlackBerry apps, but does anyone know how to configure <a href="http://www.jetbrains.com/idea/index.html" rel="nofollow noreferrer">IntelliJ IDEA</a> to build/debug BlackBerry apps?</p>

Not really an answer, but more asking for clarification what is different for Blackberry dev versus other J2ME devices...
I see its a
MIDP J2ME
device, and so the standard
Intellij J2ME
support would seem to give most of what is needed.
I guess the emulator side of things might be different... but maybe you can call the jde emulator from IDEA...
Regards,
Chris