Workbench suggestion: using custom toolchain versions?

Other than editing the Workbench extension manifest manually, are there plans to easily specify custom versions of toolchains, and point to them for local compilation?

Perhaps allowing us to declare additional toolchains in the workspace settings file will be handy. It might open up another can of worms re: workspace vs application-wide settings…

In any case, having quick access to declare custom toolchains will be great for quickly testing modified device OS firmware, or simply adding toolchain versions that are otherwise not (yet) included in the VISX file.