Never had anything decadent concerning french toast but have seen it done on grill in the past before Blackstone griddles became the rage. Was at a RV get together.
With that said I have an old cookbook around here on shish-kebab cooking and there is a recipe for french toast and fruit kebabs. Who would have "thunk" it. I googled it and sure enough there are recipes for it on the web...again who woukd of "thunk" it.
Good luck in your search.