Eventually we trusted their bond enough to move Pepper into the large cage with Pipkin, where they would often sleep cuddled together:
And this was the state of affairs when we left them together and went off to Turkey for two weeks.
***Upon our return, we found out that the rabbits had been peeing on the floor outside the cage while locked up, every day. This was unusual but I figured it was a product of boredom and frustration. Then we witnessed some minor fights and serious chasing, which I thought were mating behavior. Pepper was coming of age, after all. She was probably ready to mate.
As it turns out, Pepper was indeed coming of age, but not the way we thought. A few days later, Pepper had hopped up onto the large box that holds the rabbit supplies, and I was sitting on the floor beside it. As Pepper hopped away from me, I saw, to my surprise, furry lumps dangling on either side of "her" tail. WHOA, I said. Pepper has BALLS! PEPPER IS A BOY!!!
I was shocked and horrified and disappointed. Minor though it was, this required a definite paradigm shift! All the rabbits' behavior had to be interpreted in a new light now. Clearly the pee-spraying was actually a territory-marking contest, in which they would not cease as long as Pepper retained his male hormones. They were not going to stop fighting and be friends. They were going to fight more and more, and pee more and more, as long as they were together.
So we separated them again and resigned ourselves to another several months of climbing over a gate whenever we need to go between the kitchen and the living room. Now Pipkin is in his original small cage in the kitchen. The big cage and the living room are occupied by the big brown rabbit, whom we have renamed Hazel (also a name from Watership Down, you may notice) to facilitate a change in our perception of him. At present he is scrabbling back and forth under the fluttering curtains, shoving a collapsed cardboard box around with powerful thrusts of his hind feet.
Hazel weighs at least six pounds now, probably seven, since it's been a few weeks since we weighed him, and he doesn't look like a baby any more. He's a big, handsome rabbit: