This scenario is one that I hit during an event edit for my wife's company. Allow me to explain what I am trying to do and see if there is a solution.
I shot about 250 images for a product shoot. I was only editing and finishing 10 of them. I imported them in Lightroom and culled them mercilessly to about 80 images. I then uploaded from within Lightroom to a SmugMug gallery. I created an event for that gallery so that they could review the images and select the 10 they wanted to be fully finished. (Stray hairs removed, stray threads on the clothes, color tweaking etc.)
So once I had the selected images I did some editing in Lightroom and heavier editing in Photoshop. Where I got stumped was finding a way to use Lightroom to replace the originals with the edited files I made. However the file name is not the same anymore.
What would be the best way to do that? Is there a way to do it? I have even thought about using SmugMug uploader in a web browser but it will not accept the PSD file.