and DynaMo has been used in the excellent BreakQuest (www.retro64.com)
I disagree with TeaMonkey's comments about commercial use of Dynamo, because - as you've pointed out - it's been done with a very successful game. He's right that you still need a good collision detection library though. Dynamo is collision response only. It's apparently a very short piece of code and very easy to use though.
And it's www.nurium.com not Retro64.