I love when grapes come on a pizza thread. Actually grapes on flat bread is a classic combo in northern italy....in the wine regions. The flatbread is thick, kinda like a grandmas pie thick.
I do the opposite. Take a pizza dough, one you would normally use for a neapolitan pie. Pound it or even roll it ( yes, rolling is ok in this instance) EXTREMELY THIN. Slice seedless ruby grapes in half. Place them on dough, slice down, a good amount, do be afraid of overdoing it, you cant. Finish this simple pie with EVOO, salt, sugar, fresh thyme and rosemary, lots for fresh cracked and cook till crisp. It doesn't sound it....but it is ALWAYS the most talked about item in my catering events. Learned it while working in one of Connecticuts foremost italian restauarnt...its their house bread.........