I dont really eat sandwiches anymore but I found that a few individual things worked really well (with me anyway).
- slightly toasted naan bread + mayo + chicken
- pesto as a spread
- sausages flattened and fried and its juice used as spread
- dip 1 side of the bread in olive oil and fry until slightly crispy
- ciabatta bread is second only to naan bread
- grill bacon, do not fry it
obviously they're all separated. they dont make part of 1 freakin huge sandwich!!!