This is almost identical to a project idea I've had banging around for...um...6 years now. :) Glad to see someone is running with it, and also that you have data privacy as a 1st-class citizen. One idea for the data model: domain-specific descriptors (ex., not just a date, but a human birthdate with specific parameters (think healthcare applications: pediatrics vs general inpatient); this could be derived from sample/production data, but when designing a new application, one might need to have finer control over things like distribution (normal vs. skewed), min/max, etc.). If someone is designing a new report for an existing application, but wants synthetic data to use for dev/testing and UAT, the report "target data profile" may diverge from historical production data in very specific ways (ex., introducing new types/classes of products).