I'd take the idea of using the PCIe lane for an SSD but I would take in the opposite direction. What I would like to see is a board in this form-factor and a slot for the Compute Module. The board could then be a (hopefully cheap) dock for the CM that we could have as the basis for different modes of computing. The CM + disk could be a portable "puck" that should be easy to plug into the dock.

What would that gives us? Well, I could get multiple of these docks and I'd just have to carry the CM puck around. If I am working I'd still like to use an external keyboard, mouse and a big display. I could have a dock on my TV if I want to play games or have "smart TV" functions. We could also have a "laptop version" of this dock and it would be like the Atrix lapdock. One could even imagine a dock in the form-factor of a smartphone/tablet.

Such a system would help a lot in fighting e-waste (we would be able to upgrade only the things that need upgrading, instead of being played into planned obsolescence) and it would also be an intuitive way to get back things from the cloud and make computing "Personal" again - the "puck" with the brains and memory would be the physical representation of the things that we have, the docks would just be the different ways to interact with it.