Stopped by the ol' shop today (Bosses birthday).
Anyway, they've been using some trick tool holders. A few were first tried on their new 15,000 RPM Fadal, but they were so good that they got a bunch for all the machines, even some in HSK for the Makino.
Scroll down to page 7 MX Mini Chuck. As you can see, the shallow taper collet is held by a screw from the retention knob side. Talking to the guys, these have very little run out and don't vibrate at 15k. They are great for tiny end mills where runout can kill them. I mean the Pioneer Ad copy says all that, but who can put unlimited faith in ads.