The Igo Kapoosh knife block is very cleverly designed. Rather than a solid block of wood, with slots that may or may not fit your kives, the Igo Kapoosh block is tightly filled with slim rods that adjust and hold whatever size blade you insert into it. And the removable insert that holds the knives is dishwasher safe.
Hapa Dude has had one for a year and finds it very versatile. One minor issue: 8-inch chef knives stand up too straight to fit under the cabinets that overhang the kitchen counter.
Amazon, Bed Bath & Beyond, and Linens ‘n Things sell them for about $30.
A great knife block