I thought that the circuit would make a good headphone amp with a few changes. I added the ccs and the power Mosfet on the output and changed the biasing a little. I've written the designer of the original circuit and have his blessing to show the circuit. I've got the parts on order (most of them) and I'll let you know how it turns out.
The original has some typos. Several capacitors have been changed on the advice of Rohit. Also he modeled the circuit using an IRF530 on the output stage and say's the results aren't bad. But as they say the proof is in the pudding(listening).