People on this forum recommend having two identical hiding places in the cage, one on the warm side and one on the cool side.

What if you take a large hide box, put a divider in the middle (I don't know what the easiest way of securing it would be) and putting it on the division line of the warm and the cool side.

Then you have one hide box acting as two...

I'm not sure if the gradient would be big enough though, but I thought it would be an interesting idea.