Align nodes by sliding on path

[birdsaregood]

There should be an option in the node alignment tool to slide nodes along the path to align, rather than simply moving it vertically or horizontally.

Suggested purpose: Ability to make custom symmetrical nodes.

There are many times when I'm drawing an object and I want to add nodes on two sides of an object that are at the same height so that I can then move them with the keyboard arrows and have an even-looking object. I normally have to select the surrounding nodes and click the Add Node button many times and delete the ones I don't want. This would save time by allowing me to double-click the area I want to add the first one, double-clicking near the opposite area for the second node, and aligning them by sliding them on the path rather than by manipulating the path.