I have frameless Ikea cabs. At the ends of cabinet runs and at the end of the island, we cut end panels for high cabinets to make base cab end panels that go all the way to the flooring. I thought this was a little more aesthetically pleasing than using the standard base cab cover panels, which would have had toe kick at the bottom-- but it's a preference thing, and having toe kick at the ends is less expensive to do, and eliminates a gunk-collecting inside corner:
Where we had cabs back to back on the island, we used two end panels, with a seam in the middle. The end panels were finished on both edges, so the seam is neat, though the panels are not grain-matched as they would be in higher-end cabinetry. I have dark cabs, so the seam is not that glaring. Still need to paint that granite support!

Sorry, those are not the best pics to illustrate what we did, but hopefully you get the idea.
Q