[Tfug] Roll your own Mac

[Mr Brevity]

Hi,

Anyone been down this road before?  If I wanted to *play*
with OSX (not invest any serious time with it or apps
written for it) and wasn't picky about the hardware that
I used (assuming I had something here fit for the job)
*or* perhaps having all the features (I/O's) working
properly ON that hardware, is this a relatively easy
thing to do?  Or, a royal PITA?

Any guidance on picking (from among hardware on hand) the
best/easiest box to use as this basis?

(Yes, I see the various sites devoted to this stuff; I'm
more interested in the *actual* effort and problems that
folks have encountered... tradeoffs they've had to make, etc.)

Thanx!
--don