1024² not good enough for what? 1024² should be more than enough for an good quality!
For example, i use one 2048² Texture for more than 6 Objects ( 6 different Textures in this file) and the quality is good enough.
Do you used an NRM Shader with your Textures? This will have an sharpening effect on the Object.

regards Sebastian

btw: moved this Topic