Someone alleges they were able to reach 101MH/s with 4850 on https://en.bitcoin.it/wiki/Mining_hardware_comparison#AMD_.28ATI.29
Whether or not it's profitable depends on how many cards you're running per rig, PSU efficiency, and draw of other components. But, assuming you run 2 cards @ 90MH/s on one rig, and total, the rig consumes 300W, and say you spend $.125/kWh for electricity after fees/taxes.... No, it wouldn't. It perhaps could be if you have very cheap electricity or slap 4-8 cards in a single rig, but you probably wouldn't be seeing much profit margin, and you'd be at a high risk of it being unprofitable as difficulty/price changes while others are upgrading to much more energy-efficient rigs.
If the numbers I pulled out of my arse are way off, you can plug in your own numbers @ http://bitcoinx.com/profit/index.php