Interesting modular rigging approach with Flash based UI (Softimage XSI). The connection points between different modules can be chosen on-the-fly.
"Unlike usual auto rig scripts, Alive lets you build your own character, limb by limb, just like a Lego system.
Because all the characters don't necessarily need the same features (stretch, arm curve, roll division...), Alive lets you specify the features to apply on each limb separately."