Toast the bread in the toaster until light golden brown. Set aside.
Fry the bacon until just barely crisp, and then drain on a paper towel. Set aside.
Mix together 2 tablespoons of the mayonnaise with the basil pesto. In a separate bowl, mix an additional 2 tablespoons mayonnaise with the sun-dried tomato pesto.
To make one sandwich: Spread 2 pieces of toast with basil pesto mayo. On one piece of bread, lay some roast beef on top of the pesto mayo, then top with a slice of cheese and some lettuce. On the other piece of bread, lay the slices of tomato on top of the pesto mayo. Top with some avocado and bacon. Lift the second slice of bread and place it, ingredient-side down, on top of the first piece of bread.
For the second layer: On the top of the top piece of bread, spread the sun-dried tomato mayo. Spread one side of the third piece of bread with sun-dried tomato mayo. Place ham, cheese, red onion and lettuce on top. Top with bacon slices.
Place this piece of bread, ingredient-side down, on top of the first piece of bread. Use a sharp knife to cut the sandwich in half (on the diagonal) then again in fourths. (Use large toothpicks to secure if needed.)