I realize this is an old thread, but in the interest of providing accurate information, I'll dive in for a minute.

The bending strength (what us engineers call the section modulus=S) of a 2x4 (or any other rectangular shape) is width X height squared / 6 (for orientation - that's for vertical loading). For a 2x4 oriented edgewise S=1.5x3.5x3.5/6=3.0625 inches cubed; oriented flat, S=3.5x1.5x1.5/6=1.31 inches cubed.

Shear strength is about the same in either orientation.

Stiffness is similar, but it's width x height cubed /12. That's why a 2x6 is nearly 4 times stiffer than a 2x4, spanning the same distance.

Also, torque is force x distance, both in applied loading and resistance, so quatsch is correct for the 26 lbs at 27". To finish the loading calc, the tension on the fastener is the torque / the distance from the fastener to the edge of the base plate.