I think maybe the definition of multi-taking may be the problem here. While the Android OS does allow for multiple applications to run at the same time, it does not allow for multiple applications to be on the screen at the same time (this would be very difficult on a small screen (even the 4.3" on the droidX/Evo). The apps continue to run, but do so in the background (hence multi-tasking).
I am not aware of any mobile OS that allows you to run apps in "windows" where you can have several open/viewable at a time. WebOS has cards, but you can't see more than one card at a time (or at least you can't see the cards if you have an app active).