Just one detail that I -- and others -- overlooked:

Einstein is not an emulator in the sense that it is some kind of clean-room rewrite of the Newton OS; it uses the actual code from a Newton MessagePad 2X00 ROM.

This means that, in order to run Einstein legally, a user must also own a Newton MessagePad with its ROM (the ROM is actually extracted from the MP and used by Einstein).

But don't fret, Newtons are cheap -- for the moment...