An interesting article called The Office Chair Goes to School takes a look at ergonomics (or the lack of) in the classroom, both for students and teachers. Budget considerations may not make $1000 office chairs a possibility (the article specifically mentions an ergonomic chair called the Contessa), but it's good to know there is at least one company (Teknion) working on solutions that schools can afford.
"John Hellwig, vice-president of design and innovation at Teknion, said the company began focusing on the educational market about five years ago, creating furniture such as study carrels and "laptop environments," and components that allow easy reconfigurations."
The article talks mostly about one teacher's experiences in a grade school class, but as someone who's been taking college classes for a long time--it goes slow when you're doing it part time--I can attest to the horrendous chairs in every school I've attended (a stint in the army makes that more schools than you might think). When you're taking two or even four hour long classes, you really do notice the discomfort. So, I'll raise a reverent pencil to anyone who is trying to put ergonomics in the classroom.