Damn. Franky, I really don't think the time involved with this is worth it. I mean between gathering paper, leaves, etc., soaking it all, pressing and drying it, etc., it might just be easier to just cut down a dead tree and split it.
Of course, in a survival/preparedness situation this could be very useful, but you'd have to either have a ton of junk mail stored up or have made the briquettes in advance.
Now this is coming from a guy who lives in the mountains with trees all over the place. Maybe for someone in the burbs making these is a better option.