I have considered the dog cage ... the rollers are nice.
I settled on the idea of a platform bed where the platforn is an actual cage say 3" high ... plenty of room to stretch at least horizontally. It can have a canopy for bondage play.
I am a sadistic male Master looking for a bisexual female slave for domestic and sexual service. Hucows are of particular interest. I live in a rural area on wooded acreage.