Is it possible to emulate previous OS in an Android Device?

I'm a developer and I want to test the behavior of an app I'm building in different versions of Android. Since I have JB, I want to try my app in ICS and GB to see how it works, with minimal details such as the action bar that was added in HC. I know about the AVD (Android Virtual Device), but it's just not smooth enough for me. That's why I ask if it's possible to do it with my own device or if I have to get other devices with a previous OS. I'm not worried about if an app is supported or not. Is it possible (through a menu setting or an app or something) to emulate a previous version of Android OS? For example, my device is running ICS 4.0.4 and I want it just for a moment to try an app have it in GB 2.3.6 or GB 2.3.3 or even further?