[2008 update: Looks like Diana is being republished! Details here.]
Crayons asked me tonight if I'd read her "Anna and her hippo horse." I was drawing a complete blank until I remembered...a few nights ago we had read Edward Ardizzone's Diana and her Rhinoceros.
Yes, that was it!
Unfortunately I cannot find even one image online of the cover or artwork of this slightly surreal but much-loved story. Other Ardizzone images are around, but Diana is unavailable. (The last edition seems to have been in 1993.) If you can find a copy, though, it's an instant winner with little girl squirrels just turned four, especially those who (like Diana) have a shed in their backyards that just might do to house a rhino. And those who (like the rhino) like hot buttered toast.