I can't see an iPad3 this year.
Sure, they may fall behind technically when/if Tegra 3 Android tablets launch, but by that time it will probably only be 4 or 5 months till the official iPad3 launches, and catches back up from a specs point of view, so I can't really see that being a major issue for Apple as they will easily be able to ride that time period out based on their brand.
If Retina Displays launched on Android this autumn then it may be a harsh few months, but I'd think it's still optimistic to see the screens in the Labs actually into retail products at reasonable prices even by late this year.
Who knows, even iPad3 may not have a retina display, or perhaps there will be two iPad3 models, one with the normal screen and a more expensive model with the retina screen. We shall have to wait and see.
I could imagine Apple making the odd technical tweak (like changing panel suppliers) but it will still be called and iPad2 I'd think.