the Knoxx SpecOps on an 8.5" Grizzly is just a hair over min OAL...
...but keep in mind that the Knoxx SpecOps collapses in 2 ways: with the adjustable collapsible stock, and also with the recoil absorbing spring mechanism.
it is not outside the realm of possibility that an overzealous cop could push down on the gun while he is measuring to get it below 26". all it takes is a 1/4" below 26" and you are in deep sh*t. it would technically be a 'Firearm that can be reduced to a length of less than 660 mm by folding, telescoping, or otherwise'.
would a cop do this? would you be able to defend it in court? who knows. im not going to find out.
as much as i gripe about the NRS, this might be one case where it isnt a bad idea.