What if you made the "Into the Sunset Ending" a type of waking dream sequence in the middle of the film? Something like the Unicorn Scene. Yes, I know that was a memory, not a dream. But what about placing the "Into the Sunset" as a waking type dream (with "We where made for each other" line but not the voice over) when Harrison Ford is sitting alone in his car in the acid rain. Place it just before the cop car comes by and asks him what he is doing there. The Cop car arriving can snap him out of his deep thoughts of him and Rachel driving into a sunset together. Then you can place the call from his boss after the cop flies away, then cut to the group of street people outside in the rain walking towards Ford's car. Then cut back into the car when Ford makes the vid-phone call and Pris hangs up on him. I think it would work. It would be like he is just day dreaming that the earth was a better place then it truly is, and he and Rachel could somehow have a future together and not be so different from one another. He is after all falling deep in love with Rachel by this point in the story, and people do daydream about having a perfect future with their new found lover. Just another way to use the existing footage, but not place it as a happy ending...
FF