The most popular feature request in The Rigging Toolbox has been an IK/FK switch/blend for legs.
This is not hard to do and will be in the next major release. The lack of this feature also highlights some of the key differences between character animation rigs for film/video, and games. Some of the developers who use The Rigging Toolbox have explained their need for leg IK and I’m fully on board.
Personally, I’ve never wanted for leg IK in my characters, hence the lack of this feature in The Rigging Toolbox (yup, blame me). If a character was to float, swim or ride a skateboard I’d use a different rig with the same skeletal configuration or more than likely, a run-time solution in engine. That said, some of the new animation state systems out there and robust pipelines (including some of the new Mecanim features in Unity) could take advantage of a leg IK/FK switch and it does free up the animators to use a single rig. I’m listening, stay tuned.