Back to the inverting verlet problem for a second ... what would happen if you did a movement phase and then a constraint phase each iteration? Say, you did four iterations of quarter-speed movement with a constraint go-round after each iteration? That wouldn't put too much strain on the system, and would allow you to travel four times as fast before you might knock the verlets out of kilter.
We may have a problem in that Blitz collisions are too perfect. You can't move a pivot with collisions active so it'll partially intersect something, and you don't actually have any control over where the pivot will end up, so you have to code around that inflexibility. It also makes a difference whether you're using full-stop or sliding collisions. There may be advantages to one over the other in certain situations or control schemes. I dunno. Needs more thought.
We may have a problem in that Blitz collisions are too perfect. You can't move a pivot with collisions active so it'll partially intersect something, and you don't actually have any control over where the pivot will end up, so you have to code around that inflexibility. It also makes a difference whether you're using full-stop or sliding collisions. There may be advantages to one over the other in certain situations or control schemes. I dunno. Needs more thought.