The new updates to transform constrains look really cool and it's got me thinking about how I often want to constrain a bone between 2 other bones. As far as I'm aware, I cannot have a bone be constrained between 2 others, and so I have to set this up in the game engine with bone position overrides ect.
One use case would be to have a bone floating between a LeftHand and a RightHand, which would be useful for having a character holding an game item with both of their hands. In other software that been BetweenConstrains (like 3DSmax), you can also weight the the constrain to either side, so a game item could be set to just the left hand, or the right hand ect.