Umm, just a suggestion and it might be a silly one, but couldn't you just buy 2 and put them side-by-side?
Sure you could do it, but I would prefer to have one piece. It's kind-of like those cast iron "Man Grates." I have three of those meant to sit side by side each other on the grill. I hate them because they move around too much. It might be different if they could lock together in some fashion (<---- Maybe that is the key), but just sitting beside each other stinks. I'm picky, what can I say?!?