OSX in 2001 (the time of this story) had evolved significantly from the NeXTStep of 1996 (when Apple bought NeXT). There was a lot of work to be done to bring all the Rhapsody and Yellow Box work to a second architecture.

1.5 man-years? Plausible, I think.

This story is fairly content-free, and the source being that man-year worker's adoring wife, wrapping up a pleasant family history definitely squeaks of pablum. But the basic premise is believable. :)

If a group of people can hack together a working MacOS Classic environment for BeOS (http://sheepshaver.cebix.net/) without source-code for the all-important ROM, there's nothing implausible about this story at all.

The task of porting and keeping an OS under active development ported is no small task but certainly within the capability of a talented, knowledgable engineer.

Yes, take the account from the perspective of actual Apple employee, much more the one responsible for the side-project, and add your internet commenter "bogus" on it.

Being based on NeXTStep made it easy. People working ACTIVELY on it made it possible.

You seem to have forgotten that on top of NeXTStep tons of stuff had been added in PPC land that weren't at all present: Aqua, for starters, tons of functionality ported from OS 9, the OS 9 filesystem and much more. That NeXT had a x86 port several years BEFORE OS 10 (0.1) was introduced means absolutely nothing.

And by the time it did come out publicly, it also had a translation layer, Rosetta, to run PPC apps.