I got some of that Marmite-flavoured Peanut Butter and I'm powerful addicted to that, too.
I thought it was okay but nowhere near as good as just normal peanut butter so I won't be buying it again.
I have in the past eaten Super Noodles in a buttered bread roll. And I'd do it again.
Also, when I was young a friend introduced me to the delights of a ravioli toastie, made by sticking some of those Heinz ravioli from the can between two slices of bread and squeezing the whole thing into a Breville machine. It's a bit of a health and safety hazard though because the temperature the ravioli comes out as is incredible.