we're still trying to decide how to clad it, but we're leaning towards 2x2s on the top 1/3 and T1-11 plywood (running horizontal) or corrugated metal for the bottom 2/3.
update - like this:
kitten update:
i made good progress socializing the kittens. they were letting me come up to them and pick them up without scattering or hissing. unfortunately someone has now walked off with two of them (in separate incidents when no one was around) - hopefully to take them to good homes. only the cute whiter one is left now.