Let me give you some advice:
My first piece of advice for people with this question is that I would personally not ask this questions here - look through archived posts to see why (you can notice it because it will usually be a very long thread. I realize this is exactly opposed to the reason you asked, but I 100% believe that this is not the place to find the answer to that question - at least in my experience.
so even though i have logically opposed my right to give an answer, let me answer for the sake of the original post and people who desire to hear an opinion on this matter:
The reason I said not to ask it here is becuase its one of those heated questions - kinda like how you would never mention hybrid or something like that. But also, from what Ive read of previous posts, most people dont have experience with this (not a bad thing). Experience and opinion are too very different - not mutually exclusive - statements. Unfortunately somewhere someone has to have the experience (and there are some people who can speak from experience). But here is my advice: dont do it if you dont know corn snakes very well, meaning you should be able to identify their behavioral patterns. I think it also depends on the personality and history of each snake that are goign to co-habitate. For instance I wouldnt put a very active snake with a very inactive snake. I wouldnt put snakes together with extreme size difference, different eating behavior, etc. In the ideal case they really should be similar - kinda like you picking a roomate. Also, in my opinion, the habitat should be roughly on the order of twice as big as sufficient as the floor area for one corn snake - so nothign smaller than equivalent 40 gallon long tank floorspace. And I think another really big thing is lots of hides. Also, I think its best to do it with two new snakes. If you do it with a snake that is already lived in the same habitat for 1 year, it will take some adjusting time. Some people call this bad, I call it normal. However, this is a critical time, you really need to monitor their behavior regularly - as in several times a day.
I guess the point is its a lot of work initially, and not guranteed to work, but I believe it can work, and I do say this from experience. I could say more but I already said a lot if you have more questions you can email me bradarmstrong@yahoo.com and I'd be happy to share my experiences with you.