Hans, thanks for clarifying your design decisions.
I have the Precision dogs parallel guide and so have a couple of different track lengths. Most of the time the 48" track lengths aren't used so kick around the workshop and don't pack away easily. Also with only a single set of rail connectors there is a time investment in swapping over to the longer tracks.
I noted that a TPG-56 is been proposed with a longer 56"guide. I'm not sure what would be involved in swapping over to the 56" guide for those odd jobs. My thought was that an additional 20" length would convert a TPG-36 to TPG-56 and still pack away/ship easily. I'm sure the problems with the Woodpecker style connector could be overcome with some proper engineering that make the rails positively clip together securely, or having a TSO style level connector between the two rails would pull them together tightly and stop the gap appearing like Tom posted with the Woodpecker (or even machined threaded holes in the rails and connectors rather than relying on the pressure of the grub screws). I would find even longer lengths useful when using the GRS-16PE for repeatable cross-cutting doors and cabinet parts to specific lengths.