seriously considering doing this though
just need to find the time 
You said it! no going back now ;-) - it would be fantastic to see Mach doing this.
Last page was interesting too - "thread whirling! !!!!! what the heck is that !!!!!!!
ATB
Derek.
Well I was doing some drawings last night of an idea I have so when I get time I may just do it.
Google thread whirling should get you some info but basically looks like it would really need a sliding head for any length of threads due to rigidity.
It does look good fun doesn't it 
I wonder if there is an optimal cutter diameter for say a max of 3/4" AF hex? In our case the smaller the cutter dia the better and I see they do one 40mm dia! Accoring to the pdf example you want the cutter to be (very) approx 3.5 times the af BUT could a 'hobby' type machine cope with the high speed intermittant cut?
There is only one way to find out - HOOD GET ONTO IT! (I know you want to)
Rob 
The bigger the dia of the cutter the flatter the flat will be. As for me doing it so you can see how a hobby size machine would cope I am afraid its quite a big lathe I have, probably fit some of the hobby lathes in my toolpost

Heres my lathe, to get an idea of its size that is a 10inch 3 jaw chuck and a 32mm dia boring bar in the front toolpost.

Hood