I put an ad on craigslist and one of the people who responded said they'd be interested in painting and/or drawing me.  I feel like holding one position for hours would be harder than modeling for photos, so what do you think would be a reasonable rate to charge without going overboard?

ok.. first off. don't worry, you won't pose for loooooong hours without moving. They are usually 15-20 minutes work time and then there's a break. At least in my experience in class.

What I'd recommend you to do the most is play special attention to where your hands are placed, and what position they are at, that way if your arms are int he same position your back will be similar.. and relax that's the most important thing. if your are tense u'll get tired easy!

I know that our models get payed 10.25 an hour.. which is crap. since they pay students minimum wage at my universty.. and i mean MINIMUM as in 5.15 to office employees.

Well, this isn't for a class.. It's just for a person who'd like to draw/paint a model.  I don't know if that makes it any different or not, but I just wanted to clarify.
Thank you for the advice.

Bid this work on a case-by-case basis. Research the artists work to see if it's an illustration job for publishing or something meant for a gallery or personal collection. Is his work actually SELLING? If he's an illustrator, he's making a little money and is going to work from photos he shoots of you, so price it like any other commercial shoot. If he's doing pure, fine art, drawing or painting you from life, he's probably not making much and won't be able to pay much more than a school would ($10-$15 per hour) Art modeling is not big bucks. If you don't want to do it for the love of art, you won't be happy with it.

I've worked with a couple of artists before and what they all did was just take a bunch of pictures like a normal photoshoot and then use them to do the drawings/paintings after. (And these were a lot shorter than most shoots I've done.)

Maybe you should ask how they work before charging them more? Just to be sure, because it might not be any different from a regular shoot at all.

all the above is good advice.. I've worked as an art model as well for 7 years and it is not easy. If they want you to hold pose rather than take referance shots, The fee is any where from $10 to $20 hourly, depending on your location and their budget. It's kinda Bass akwards as far as pay goes. You'd think the work is hella harder on your muscles and body for sure than Photography but for some reason the pay is by standard much, much, lower. If you're just starting, $10 to $13 an hour is good. If they want pics, depends on what kind, do they just want your face or a hand position stuff like that then tack on and extra $30 0r $40 bucks for the whole deal, but if they want a full out shoot to referance you by then they should be paying photography rates cause they'll have your image anytime they want and that's not fair to the model. Some artists will even trade you or you could ask them to paint you a portrait if you want. And yes, pose for 15- 20 minutes at a time then take a break and stretch or you'll be sorry for days or weeks afterwards!

i work as a figure model full time and my experienced answer is... "it depends"
i don't know how much the schools pay there, but out here it's anywhere from $11-15/hr for the most part. so, based on that, most of the other models i know charge a bit more, because it's a bit more of a hassle (not to mention a potential personal security issue) to work for one private artist in his or her studio.
the few times i've done private work i was paid $20/hr, but i know of co-workers of mine who can demand and receive more.
then again, i've also posed for friends of mine, struggling students themselves, and in those cases i worked for way less, if anything at all.

so working for friends = paid less then normal, maybe in food or drinks.
working for schools = whatever they decide to pay, non-negotiable.
working for professional artists (or rich dilettantes) = around double(ish) what the schools pay, if you can.

it's hard work, and don't be shy about asking for breaks.
the longer the pose, the more wear it's going to put on your joints, and the more you need to stretch and shake it out.
if something hurts, say so early.

It depends on your experience and ability to hold a pose for longer than you would in a photo shoot. I have posed for a lot of artists for painting/drawing/sculpting and usually make between $15-$20 an hour for about 3 hours at a time. You usually hold the pose for 20 minutes and then take a 5 minute break. Some artists will also agree to paying a percentage once the painting is sold so make sure you are clear on whether or not that is also part of it. Good luck!