opengl - How can I improve the performance of texture switching without resorting to atlasing?

I'd like to use texture images that are not a sprite sheet or other form of texture atlas, mainly because I'll be consistently adding and swapping textures while I figure out the direction my game takes.

In Java, I'm using slick2d's TextureLoader to load a texture, and then I bind it with an unique id. However, when not using a spritesheet I have many more images to bind, which causes a potential performance problem. I've noticed that calling glBindTexture for every block I'm drawing is bad, it drops my FPS to 1.

I'm already rendering blocks with glCallList so I've found a middle-ground. I bind a single block texture and then render all blocks of that type in the chunk, and repeat for each unique block type. However, that's still less than preferable.

Is there a better way to efficiently use multiple textures without an atlas or sprite sheet?