If you have uniformly speckled granite, a seam won't really show. If you get dramatic swirly granite, two bookmatched slabs make the seam a very excellent upscale feature.

Sooooooo depends on the granite. But seams aren't always to be avoided at all costs.

If the seam will be obvious how about dropping the end piece 6"? You will still get the storage but it will be a separate piece - so no seam on your long stretch.

There are quite a few granite slabs that reach 126". In general, the ones that have more fissures will be smaller since they tend to crack easier on those fissures. Something like absolute black, you can easily find a one piece slab that size.

Not sure what the big deal is about seams. Find a decent, reputable fabricator with a good seam guy and you won't see it at all.

My husband was really unhappy with the seams in our last house, so he is pretty against it. It was our first experience with granite, so we've never seen (or at least noticed) what good seams should look like. We had Santa Cecilia there. We've been looking at Blue Flower, which I'm told never comes longer than 9.5', and has quite a bit of movement. One guy told me almost everything from Brazil will be 9.5'. We also looked at New Caledonia, and I'm not sure yet if that one does. Dropping it 6" is an interesting idea. I'll have to run that one by my husband and see what he thinks.

Here is an example of an island with the step down. From Houzz if I can attach it correctly.

https://www.houzz.com/photos/my-houzz-traditional-home-with-cottage-flair-transitional-kitchen-phvw-vp~2618675-Houzz--Traditional-Home-With-Cottage-Flair-traditional-kitchen