Any chance to find out about device type (Argon, Xenon, Photon) at runtime?

At run-time, I think you can only grab the device ID using System.deviceID();. I don't know if you can grab the device type from the OS API. There's a good example of getting device information as a Particle.variable in this post:

As far as knowing the Argon/Xenon/Boron device type, you can do that at compile-time using the example in this post which uses PLATFORM_ID: