I see these type of things all the time on facebook, but this one just looks a little too good to ignore.
I can’t do the bread, but this is a great low carb alternative we’ve been using lately. I’d probably reduce the amount of bread, too, but have been making breadless Reubens for years. Love the idea of a larger casserole with some low carb bread: http://www.amazon.com/Mestemacher-Protein-Bread-Ounce-Pack/dp/B00T72S8EW#customerReviews
I’ve seen recipes for soups based on both stuffed cabbage and the Reuben, and have freestyled my own takes on both. Making them as soups allows starch to be minimized or not, dependent on your preferences.
That reminds me. I once made this Reuben Pizza from Sara Moulton and it was quite tasty. I need to make it again. That casserole does look delicious and sounds quite easy to throw together.