Now working with JBoss AS7 / WildFly!
As the need for a simple standalone data retrieval tool similar (or equivalent) to Twiddle has emerged, I have created a minimal standalone distribution of twiddle (from JBoss AS 6.1.0.Final) that requires no JBoss AS installation.
It is available at https://github.com/swesource/twiddle-standalone. Fork it, read and follow the README (don't forget!) and get that data!
New update: twiddle-standalone has been updated to work with the remoting-jmx out of the box. Users of JBoss AS7 / WildFly rejoice! :-)
Old update: To use twiddle-standalone in AS7 (which relies on remoting-jmx), follow the instructions Kim has supplied in the comments below. Well done Kim!