Share Data & Queries Between .pbix Files?

Hi brianmcavoy,

So far you could not reference between multiple pbix files even though you could use Q&A feature with tips to query with natural language from multiple reports/datasets in dashboard. but this approach is good when

• To get basic insights from multiple reports
• Your query is just basic without complex formula
• Have good preparation of data model and naming convention or good synonym for your model 

Which is good between creating separated data model and combination?

In my mind, there is no one good or not good. it's your ability to design & maintain based on your organization needs. In the first stage, we just implement specific reports for each departments, so it's good to have separated data model that fits their business (operation or financials). There is no confusing and no redundant. 
After that there are some needs from higher managements that they need information from both of Fin & Op, so in this case we need consider their requirement basic or complexity

• With basic need, sharing report/dashboard feature or group user are still works well for them.
• With complex needs, we need combination data model to cater some complex formula/metric as you mentioned.
  1. More effort to maintain(comply best practices such as naming convention, business patterns, etc ...)  or documentation for changes (Data flow, data/fomula/expression definition, changes)
  2. Some limitation in technicals such as Direct Query will not allow mixing sources, different latency or refreshing schedule between data models and different of connection mode (import/DQ). 

To combine 2 data models, you just do it manually by copy queries in Query Editor, calculated measures/columns. The layout of reports will need to be re-created manually :( But the good new will be updated in the end of Jan-2017 as https://ideas.powerbi.com/forums/265200-power-bi-ideas/suggestions/14114169-allow-copy-and-paste-between-different-pbix-s