We use Rabbit Shelters like this:
and here's another design:
Design details:
Design for flat ground:
A design from Egypt:
And here's ours in a barn:
And how we made them:
http://velacreations.com/blog/352-rabbit-dwelling.html
More information about this system:
http://ressources.ciheam.org/om/pdf/c08/95605275.pdf
They work great in places that get a lot of heat. We breed year round, and it gets hot here for most of the year. I read about people losing rabbits in cages with water bottles, misters, fans, etc, and I can't imagine all that work and effort to do something that the ground will do for free. The shelters are easy to make. We used brick, because we already had a bunch of spare brick. You basically make a box that is buried into a hill/berm, and then a cage on the outside. Use something like concrete or brick, ceramic, etc. The rabbits kindle in the box just fine, and we rarely lose kits.