First off this is my first post , this is a great forum with a lot of helpful information. I raise American Giant Chinchilla rabbits. My cages are 48 x 32 I also dont like the wire floors but I dont like cleaning much either, plenty of other work on the farm.
My floors are rough cut oak boards that are 1inch x 1 inch with a 3/4 inch space between each slat, I am sure any wood would work just run through a table saw , still let's all the waste fall through and give's the rabbits a solid floor. My cages are ply wood boxes so I just cut the slats and screw in from each end/side. I have had some of those cages about 4 years and floors are still solid.
Hope that give you some Ideas.