Once you're looking at a good high-end PSU aren't they all fully modular anyhow? I have quite the fetish for Seasonic, and generally won't touch any other brand (unless it's a re-badged Seasonic ). All the Focus PX range (which are not stupid expensive) seem to be fully modular.
You pay for the quality of the PSU. It's one component where it doesn't pay to penny pinch.