I see a huge, annoying jump into and out of Mercator.
A bit of tweening animation should be able to fix that though.
That's really cool. Thanks for sharing.
It messes up around Antarctica, but it works much better than mine, which doesn't even exist, so I should probably be quiet.
As far as I can tell that actually could work very well, though the implementation might be quite difficult: 15 different zoom levels (I think) that google uses probably wouldn't be enough to make transitions between each seamless, requiring client side scaling during the zoom animations (which will either make the images slightly blurry or require loading higher resolution images).
Of course. The real challenge is making it look good with pinch-to-zoom.
Yes, and considering that Google Maps can use WebGL with vector graphics, it would be seamless.