Place custom snap points onto objects

I got this idea (feature request)

Background:
When rotating an object I can move the rotation center free around and snap it to any other (or same) object. I think that's a nice feature. Also the concept about guides is a really nice thing.

Exept from guides and rotation centerm There should also be another object free to move around. Let's call it a "stitching point". In my mind I think about a POINT that is connected to a specific object. Idea is that this point would move as the object (that "the point is stitched to) moves and rotates.
And - the "stitching point" will be able to snap, just like any corners to that object.

A specific example:
I import a picture of a face. There is a little indent in the ears. I want that indent be able to snap to other objects. I want that BOTH ears shall be possible to snap.

Also there could be possible (If two or three points exists for an object) to keep down Ctrl+Shift (or some combinations) while dragging one point in any direction to the other points.
If two points is inserted to the object, both width and height is adjusted proposional. When three objects is stitched to an object, both width AND height can be adjusted this way.

I got the idea because I use Inkscape to draw a room and some objects in that room - or planning to install in the room. Later on I create a layer wher I add pictures of the objects in the room (seen from above). Because one Inkscape pixel represent one cm in real life, I have to calculate the factor I have to resize those objects.

With this features included I never have to do the calculator work again. I know where in the room it shall be (exact location of the edges). So I just put two "stitching points" in each corner of the image. Then I just move each "stitching point" to the its real position on the floor (edge of a rectangle representing the imaged object) and the object will then be correctly resized and rotated.

Thanks :)