Hello Jon,
Netduino is part of the older family of board and these have been superseded by the Meadow family of boards. These boards utilise a more powerful processor and make more RAM available to the application.
Meadow is targeting .NET Standard in the version 1.0 of the software (the OS is currently in beta). This brings modern C# to the microcontroller world.
Meadow is currently available on the Feather form factor. An embeddable module is on the way. It is also intended to release schematics and documentation to allow for the system to be tightly integrated into your product should you wish to.
Hope that answers your questions,
Mark