Bug: Creating a schema only layer package for multiple layers from different geodatabases creates the schema for only one of the chosen layers.
If the layers used to create a schema only layer package (.lpk) reside in different geodatabase workspaces, the unpacked .lpk will contain the schema for only one of the layers chosen for packaging.
This is a known issue in ArcGIS 10.
Use the Consolidate Layer geoprocessing tool located in ArcToolbox > Data Management > Package with the 'Schema Only' option to create a new folder containing the geodatabase workspaces with empty feature classes and layer files.
Use a third party program to compress the new folder and its contents for sharing.