I also hope that they put this in production, it looks really interesting.
When designing the simulation phase is mostly to verify that the design is ok. So it's doing the the design that is the tricky part. And when doing discrete designs you really must know how every FET/Transistor works/sounds and how to get the best out of them, there are so many factors that affect this.
Here is one of my discrete designs, it might look simple but i think i spendt over 3 months testing different designs/components etc. (for all schematics): http://bozure.com/T1.aspx?PID=58