I'm currently working on a 10 page, full color comic and its going well. But then again, he's also paying me by page before I start on the page(s).

Never finish any work for someone without payment first! Even sketches can be risky. Ask for payment if they start hitting you with more revisions than you can stand. I've had some people present me with huge character design or illustration projects and then disappear, but on the other hand I've been working with a few series commissioners for over a year now. We just do payment one or two pieces of art at a time.

Unfortunately, there are people who talk a lot about their "great ideas", but never actually do anything with them, or want to "commission" an artist to do them but have no way, or even any intention to pay for the work if they talk you into it.

Its best to require payment up front, with an understanding that the finished work is what they get.
(No one has the exact sake "artistic vision" of what something will look like when done to even a written description, so a serious buyer will, and must accept the version the artist does.)

The real nightmare is someone who has no idea what they want- but they know that nothing you seem to come up with is "just right" and ISN'T what they want....
Someone like this will run you ragged with demands for changes or revisions until the job isn't worth what they paid you for it.

Yeah, major "epic" commissions can be worth the cash- but always write down a set of rules that the buyer must agree to before you accept the work- including a specific mention of what or any revisions are allowed, and at what stage of the work.
(For instance, no changes after inks are laid down simply because you can't really alter inks very well.)

An indecisive buyer can ruin your whole day- or whole year, if you let them do it.
If they won't agree to a set of rules for the commission, or give you a snotty attitude because you want to impose them- don't take the work in the first place.

There are some nightmare commissioners out there, and its best to avoid them.

-Badger-

When it comes to the bigger commissions that take more committment and money, I like to get to know and trust the buyer befire selling, especially in the furry fandom. It's different if it's a children's book author approaching you, it's easier to check out their background, and easier to back out.

I myself have had at least one big commission as you mention (at least that I can count while being too lazy to check). And I'm currently committed to two or three such jobs. It's not a bad idea, you just have to be careful and choosey about who you work for in these jobs.

Someone wanted me to do the cover of their book. I spent eight solid hours on the cover, it turned out nice and vivid, and then she decided she was going to go with a picture from her editor. I never received a dime for my hard work.

Yes, it's possible. For every bad commission problem you hear from someone, there will be many, many good ones that have happened and no one has spoken up about. ;) I did a 5 page comic for a great buyer a while ago. Great guy named Gary who was friendly, understanding, had great communication in what he wanted, etc. He did pay up front for it. Just for the record, I do say understanding due to the fact that I had taken longer than I hoped due to health problems and recovering from being hit by a hit and run driver. I did make some custom magnets for free and gave them to him in apology. Back to the point though...

There are good buyers out there for larger commissions, but while some are iffy about paying a full amount upfront, at least get half up front and keep in constant contact with them regarding updates and feedback, etc. I always wait until I get some payment (half or full, etc as agreed upon) before I start working on commissions, that way I know the buyer is interested and it will yield some results from the buyer. If they don't pay, I'm not out of time worked for nothing. I also second with Ironbadger and Auradeva about the set of rules on revisions. I got stuck in one commission like that with a different buyer. I had to put my foot down, twice, after it started getting out of hand.

-Tigrr Wildcat-