While the Soul Cages from Soul Shards are awesome in every aspect of the word, the texture they use has always bugged me. The mod creator lazily copied the Iron Bar texture, only adding a few extra bars so it tessellates better. Sure, it fits the recipe, but it still seems a bit bland. As such, I decided to make an alternative texture.
Keeping with the Iron theme, I used bits and pieces from Iron Bar texture and put them into a spawner lattice pattern. It's hard to see the detail in 16x16, but with the 32x32 version, you may notice that I've layered the bars out to make them look like they weave together. The textures are also a nice alternative to the vanilla spawners, in case you want a different one.
The textures I've made are below. The small one is the 16x texture, while the larger one is 32x. You may use them however you like, whether it be personal use or in a texture pack. Just give me credit if you wish to redistribute them.