i think you guys are conflating illustration work with comic work.  two very different animals, as far as i can tell.  there's a reason most comic artists don't seem to stay in the industry and move on to doing illustration.  everything i've heard is that it pays a whole hell of a lot better.    most of my favorite comic artists are now doing illustration and won't touch comics because of how much work you're supposed to do in how little time for how little money.   the ones that do still do comics tend to do a lot more  illustration.

again, i know of the industry only by being a semi-collector and perusing a few sites and forums heavily at one point (and noticing the turn-over in artists every 5  to 10 years or so), but my impression is that comics are a lot like the gaming industry.  the mystique is such that it attracts a multitude of talented, and young, individuals, the nature of the work is such that it requires an incredible amount of work to do even the most basic project, and  the market is glutted with content so that it's very hard to get any money from customers, let alone lots of money from customers.   so companies work young kids into the ground, burn them out, and then they move to the more reasonable pace of something like advertising/commercial illustration (which actually burns out most other people). 

but i could be totally off in this.  it should be easy to check.

you shouldn't ask here about how much to do a comic.  you should ask at a comic forum, like comicon.com. try contacting jvanfleet over at Daz.  he's a favorite artists of mine who has stayed in comics, and is now using Daz figures.  John Van Fleet  did Batman: The Ankh, Batman: the Chalice, Vertigo Shadow's Fall, many issues of Hero in 2003, and illustrated the (fairly) recent Batman #663 written by Grant Morrison.