Actually, I already had a 45 but dropped it onto the concrete garage floor. In a fit of despair, I bid on this 45 on eBay and won. Meanwhile I was able to repair the cracked main stock on the first 45 so now I have two of them working. Neither came with an original box which was likely cardboard anyway. Hence this project. Guess I will have to build two of them.

The first photo shows the plane side of the spine. The peg at left hooks the front of the skate on the 45. The plane then is lowered till the skate sits on the horizontal wooden ledge. Three magnets grab the main stock skate while the bottom of the wooden fence sits on a thin strip of Oak underneath the spine.
 

Finished Box Spine.

A Stanley 45 has sort of a turned up nose on the skates. That fits under the peg. The flat strip of Oak under the Rosewood fence is necessary and is cut away at the front because the front tip of the fence pivots down a bit while hooking the plane under the peg, and needs additional clearance there.

Hooking the Skate Under the Peg.

The main stock side of the oak spine has to be relieved to accommodate the slitter stop and the depth gauge and there was minor chiseling near the dowel to get everything to fit.

It was my goal to not have to disturb the planes settings just to put it away in the box. Usually that succeeds, though the fence does have to be close in and in the higher of its two positions.
 

Main Stock Side of the Spine.

This is the new Stanley 45 plane nestled in its docked position. Its snug and the magnets hold it down pretty well.