public interface IBaseProvider
{
    void Configure(IDictionary<string, object> configValues);
}

public interface ISqlProvider : IBaseProvider
{
    ///CRUD omitted for clarity
}

public interface IBlobProvider : IBaseProvider
{
    ///CRUD omitted for clarity
}

public interface IDocProvider : IBaseProvider
{
    ///CRUD omitted for clarity
}

public class SqlDataProvider : ISqlProvider
{
     public void Configure(IDictionary<string, object> configValues)
     {
           //Do stuff
     }
}

public class DocDataProvider : IDocProvider
{
     public void Configure(IDictionary<string, object> configValues)
     {
           //Do stuff
     }
}

public class BlobDataProvider : IBlobProvider
{
     public void Configure(IDictionary<string, object> configValues)
     {
           //Do stuff
     }
}

public interface IProviderLocator
{
    T CreateInstance<T>(IDictionary<string, object> configValues) where T : IBaseProvider;

}

public sealed class ProviderLocator : IProviderLocator
{
     protected IDictionary<string, object> configValues;
     public T CreateInstance<T>(IDictionary<string, object> configurationValues) where T : IBaseProvider
    {
        configValues = configurationValues;
        return Initialize<T>();
    }

    private T Initialize<T>() where T : IBaseProvider
    {
        //reach into the configuration system to get providerType
        var provider = (T)Activator.CreateInstance(providerType);
        provider.Configure(configValues);

        return provider;
    }
}

var database = new ProviderLocator().CreateInstance<ISqlProvider>(null);

public interface IProviderFactory<T>
{
    T CreateInstance<T>(IDictionary<string, object> configValues)
}

public sealed class SqlProviderFactory : IProviderFactory<ISqlProvider>
{
     public T CreateInstance<T>(IDictionary<string, object> configurationValues)
    {
         return new SqlDataProvider(configurationValues);
    }
}