Still thinking about this? I've another suggestion: instead of a book, how about packaging up individual tutorials and selling them digitally via tutsplus.com? This would allow you to throw together working resolution files in cpt and psd formats with masks/objects/layers intact and not have to worry about editing to fit the space constraints of a printed manual.
But mainly you'd get paid for each tutorial along, so you'd be less overwhelmed trying to complete an entire book before seeing any return on the effort.
OMG yes, ecstatic yes! I probably have no grounds to tell you anything, even so here’s what I think: I’ve shelled out a ton of cash over mostly useless tutorial books that essentially said "PRACTICE MORE" and also looked up countless free online ones that said the same, if anything I'd want it to be extremely detailed and helpful about all the sorts of things you explain so well at conventions that actually make sense. if it's just a giant glossy paper book with your pictures and a couple words I’d be disappointed, and if it's just a book with a ton of text that essentially tells me to practice I’d be even more so; I've seen and read tutorial books like both of those and neither are usually helpful. I don’t expect you to remember though I’m the guy that hung out with you during last year’s comic con asking questions while you drew commissions and I learned more from you in an hour than in a dozen books, if you explain those kinds of things with some easy to follow illustrations it’d be one of the best books I’ve ever seen; I often kick myself for forgetting the things you showed me and wished that I had some reference to look at again and remember how what you’ve explained worked. It’d also be great to see a muscle related section like your ibuki muscles drawing, during cons you've explained muscles and anatomy in ways I’ve never thought about and never seen anyone bother to talk about, simply seeing the anatomy is different than you showing why it’s like that, which is something you do well.
I also agree with KingNot about publishing online, I'd eagerly pay 10 bucks for a tutorial from you, and if you're worried about piracy I guarantee one of the first 10 people who buy your book will rip out the pages and scan them and it'll be pirated in no time, if even terrible tutorials are tossed around the net yours probably won’t be an exception. The way I see it most of the people that are big on pirating wouldn't buy it whether or not they couldn’t download it anyhow so they're kind of a moot factor. ( [link] there’s an example of what I mean. Thanks Penny-arcade!) Although it's easy to download “How to draw” books I still have a bookshelf full of them. Ultimately people will buy your book because of how they think and feel about you and your art, if you sign it for free that's even more incentive for fans to get it, otherwise you're just another tutorial out there in the sea of millions of other ones. Also have you considered a video tutorial? I’ve seen a lot and they seem pretty easy to do and can be really helpful as long as you avoid that sped up video with you dubbing over it, that can be annoying because the artist tends to end up rambling if they do it that way instead of being involved to what’s being drawn; it might be worth looking into since making one’s got to be easy to make these days. Sorry I’m long winded, I imagine if you posted the poll you wanted some feedback aside from fan boys screaming, I just want to help you in some way like you’ve helped me and everyone else. :3