Well... this is just me but 1k x 1k maps can be too small if you need tight closeups in a say TV resolution render...

Anyway, a good way to render scenes with large textures is to use the command line renderer. Not only you have more system resources available but you can do other tricks too. For example you can force the width and height of the rendering tiles (or buckets) to lower than the deault which will result to lower peak memory consumtion...

Do a search on "Batch rendering from the command line" in the docs and you'll find all the details...