Have you visited HP's website and LOOKED?
Here is one that is not to expensive and fits your details requirements:
HP, LaserJet 5200dtn Monochrome Printer
- Print Speed: Up to 35ppm
- Resolution: 1200 x 1200-dpi
- Duty Cycle: 65,000 pages per month
- 80MB of RAM
- HP Jetdirect fast ethernet embedded print server
- Automatic duplex printing
- 100-sheet multipurpose tray one
- 250-sheet input tray two
- 500-sheet input tray three
- Print Cartridge
- 1-yr. limited return to HP warranty
- Cables sold separately
$2500