I just submitted this pull request to enhance the capability of the FubuMVC.Spark bottle to allow _partial files to be locatable in other packages based on dependencies set up in the SharingGraph.
Example:
GlobalPackage
Package1
with a view.config in GlobalPackage "export to all" which sets up a dependency between Package1 and GlobalPackage
If a view in Package1 references a _partial from any shared folder location in the GlobalPackage it can now be found and rendered.
This ups the spark version to 1.7.5.0 to include the new hook for providing your own IPartialProvider, for which there is a FubuPartialProvider implementation.