The HP laserjet printers I have seen out on the market all show a duplexing option in the driver. If the printer doesn't have an actual duplexing unit, it will print out the odd pages in an orientation that you just grab them off the top and put them in the paper tray. Once there, you hit a button and it then prints out the even pages. It's been handy on my color laserjet I got for home, since I don't have to manually remember to print only the odd and such.

The Laserjet 1022 seems to be the entry level printer we have now. A friend of mine just got his recently, I'll have to see how he likes it so far.