Model for Distributed Database
If you are looking for data models to start with, I'd recommend you take a look at: http://www.databaseanswers.org/data_models/index.htm

This is the most comprehensive list of data model examples that I found so far. In fact I have used some samples as starting point for some of my projects. These models won't show you how to take horizontal fragmentation into consideration, though.

Update:

You may consider these basic techniques for horizontal fragmentation*:


Range Partitioning: Each fragment is assigned a different value range
Value List: For each fragment a list of attribute values is given
Hash Values: Applying a hash function to tuples, each fragment is
responsible for a given hash range


*Source - Distributed Database Systems: Fragmentation and Allocation by Katja Hose, Ralf Schenkel