Hey Danbo,
I have had a really hard time finding a horizontal cutter myself, but I will say that I wrote to Perfect Cheese and asked for a cutter with a size that they didn't show and John the owner was willing to customize it. I'm wondering if he was capable of welding two cutters together to give you one that is bigger than 8" but would cut what you had.
Just a thought. I've hunted up and down and have had very little luck.
Sam