Okay, so this is an area that's big business, and with big business, come patents. This is not surprising.
This page links to quite a few. Some describe a crumple zone, but achieve it by means of sliding parts (sounds awfully like MIPS).
This appears to be the Zero1 patent. If Vicis come to the party and decide to adapt their design to motorcycle/bicycle applications (and they are most welcome to), that would provide the marketplace with an alternative solution. I've attempted to make contact with them, they may be interested.
As for this project, well, one of the goals is to come up with a model that can test the effectiveness and to push for updates in the standards that take this model into consideration.
That said, we can probably get by without the use of "filaments". Could the cones on the design I scrawled on the home whiteboard be considered "filaments"? Possibly. We can also forget panels that slide around. That's been done.
A honeycomb-like structure of soft-rubber is another option. It could cover a conventional helmet, and be covered itself by some sort of shell for aerodynamic properties.
The walls of the cells would deform when struck, and so would cushion the blow, and should survive multiple impacts. The questions are, how thick and how stiff?
Something the size of a beach ball isn't going to fly no matter how good it is.
Pressure on the brain isn't in itself the damaging bit. Scuba divers and free divers regularly submit themselves to as much as 6 atmospheres of pressure. This is uniformly applied to the entire body -- brain damage doesn't seem to result, nitrogen in the blood is a bigger problem. The key thing this pressure is applied gradually. It is not an impulse.
We need to dampen that impulse. Critical damping, so that the brain doesn't bounce hard.
Time for some analysis.