One of my favorites. I tried a vegetarian reuben at Remedy Diner in Raleigh, NC, and I loved it. So, I came up with my own version, which melts in your mouth.
The pictures should explain the ingredients. I cut strips of tempeh (usually four or five fit on a piece of rye bread) and saute them in barbecue sauce. I heap a generous amount of butter onto the skillet and place a slice of rye over it. On top of that I place the sautéed tempeh, followed by Swiss cheese, sauerkraut, Thousand Island dressing and top piece of rye. Cook over medium or low heat, careful not to burn the bread, and flip to brown other side.
J. Schlenker 
Now that is good food!
Interesting, I had to google tempeh!