I was thinking about this a few weeks ago. It's definitely possible but the science behind this requires either someone very qualified or a decent amount of R & D time. It may be worth the small expenditure, could be good for marketing also if SOE could put an article out there in the press that their Matrix game is one of the first MMO's to include this technology.
The idea is that the single in-game camera would be switched off and there would be two virtual cameras next to each other. One for left eye one for right eye. When the two streams are seperated by the Glasses it gives the feeling of depth like you are really there.
Rendering two cameras in real time could be more demanding on the system since it has to calculate all the lines twice, however character positions, animation and textures would only need one space in memory so maybe it wouldn't have that much of an impact on game performance for lower end systems I'm not sure.
Ideally in the options menu there would be a Sterioscopic or 3D option, this would turn off the centered camera and replace it with two parallele cameras, one for each eye for those with the special glasses.
This is something that if you do it wrong you will make people feel sick real bad, but if you pull it off could be quite amazing, especially with things like hyperjump and slow motion. Also you would probably only want to have this option turned on for an hour or two, otherwise the sickness & disorientation afterwards would be too much ;P