I still like the gas-powered toaster I've seen at a restaurant. It was a big device that could toast 8 pieces at once. Looked a bit like a vertical rotisserie.
I used to frequent a breakfast place in Culver City that had something like that.
They were so busy that they had to make their toast that way.
Back in the day when I worked for McD's we used a drop through toaster for the buns, it was fast but I don't know if it was faster than that conveyor-toaster from that restaurant.
The difference was through-put. The McD's device had a wider mouth and you could drop a lot more slices into it at once.
So maybe even if it was slower at toasting its total capacity was higher.
Took up more space though.