...and check the business printers. Yes, they're more expensive, but they're built for the task and you can check the output ratings to make your comparisons from.

Just an example, we recently purchased an Okidata C6050 for our office which has a similar workload level. (55,000 page monthly duty cycle.) We needed a color laserjet which also had a parallel printer port and such tools aren't easily found. If I remember correctly, it was about $450 US. So far, although we're probably putting about 2,000 pages a month through it, it's doing fine for about 4 months.

Point is.. there are a number out there but you'll want to check the business machines for their duty cycle ratings.

Hope this helps.