Customizable step size when SHIFT-nudging

Currently, you can customize the step size when you move (or "nudge") your
selection with the arrow keys.
However, when you apply the shift key when moving, the selection is always
moved by the step size X10.
I'd like the ability to edit the multiplier - or step size - for this
action.

The reason I'm requesting this is for icon creation:
When editing multiple icons in the same file, it is helpful to have keys
that move them by multiples of 16, or 24, or 32, while still retaining the
ability to nudge shapes by single pixels.