Best Workflow/Setup for Swapping Shaders based on Build Target

We have a simulation project that builds for both webplayer and desktop targets. Large projects with lots of material/shaders already assigned.

We are now looking to offer it on mobile as well and are doing some initial research.

I had assumed when we switched the build target to iOS that either a) the default unity shader associations would switch to their mobile versions or b) there would be a way to setup the mapping in the editor. I didn't see either.

How do most people doing multi-platform developing work regarding different shaders for mobile/desktop?

Do you have editor tools that loop through and update to mobile shaders prior to building (based on target platform)?

thanks, dryheat70