Square Taper or Octalink ?

but that is chainline not Q factor.
Q factor could easily be addressed by design of the arms in relation to axle if any manufacturers could be bothered.
And looking at gizmonds comments it would appear they need to to satisfy the 130mm Q factor hungry track racer. But we all know teh track market is so small than it will always come a poor second or third anyway!

But your feet need to clear your chain.

I was looking at the KCNC K-Type MTB cranks fr my 29er (sexy and light). Turns out all the racers are snapping up the older ISIS version for a bit of weight saving (very little), and the better Q-factor.