After looking at that last link from Chris, I got to thinking: Has there ever been an R2 Grille (an actual, functional one) made and marketed? I'd imagine the top "dome" flipping up to reveal the grilling area. It could be either gas or charcoal, but if it was gas, the tank could be stored in the lower part. I'd also think there would be slots (similar to the link) for your different grilling tools (tongs, spatula, etc.). Plus, like the real R2, there would be wheels on legs and torso that would allow you to wheel it around.
I could go searching for this myself, but I figured an R2 expert such as yourself would know if such a thing ever existed. If nothing else, I would have thought that at least one hobbiest would have thought to do this. It doesn't seem like it would be that difficult to do for a person with basic metal-working skills.