I have twin two year olds and they are most definitely in toddler beds. I wouldn't even consider putting them in one bed because I want them to develop a sense of self and independence as much as possible.
Twins run in my family like crazy, and when I found out I was pregnant with my twins my grandmother gave me ALL kinds of advice. She was the non-dominant twin, so most of her advice was geared toward supporting and nurturing MY non-dominant twin. I got alot of advice about not dressing them alike, giving them their own rooms, their own clothes, encouraging them to pursue different activities, and treating them the way I would treat a singleton as much as humanly possible to give the non-dominant twin the ability to move out from behind the dominant twin's shadow and become his own person.
Let me ask you this: If you had two boys, age two and age three, would you be wondering whether or not to put them into the same bed? If your answer is that you would almost certainly have them in separate beds, I would submit to you that that should be your answer!
(And from the mama of twin two year olds to another: Aren't the little monkeys just SO much fun to watch?!?! The way they interact with each other and everyone else is just a hoot! But OMG do I understand what "chaos" means these days!)