@Engelbert - You can get prints in a wide range of sizes with custom sizing online relatively easy. Not too expensive, either. You can also try your local or state art gallery, some have a prints section. You could even try certain bookstores.
I'm a big fan of his as well. I think my favorite Paul Klee painting would have to be Castle and Sun; the colors and off kilter shapes which form the abstract castle and the red sun in the dark red sky, it leaves me in awe. I have a print of it in my studio.