IE-9 specific favicon?

So with IE9 around the corner, the favicon is evolving as along with pinning and such we need 64x64, 32x32, 24x24, 16x16 favicons.

This makes the actual favicon quite a bit larger (file size). Is there some way we can display only 16x16 to all browsers and just serve the larger favicon file to IE9 users?

Conditional comments.

Conditional comments for ie 9 would ive the only way for ie 9 to have a unique favicon. Because there is a way to make a specific favicon for all ie versions
But I do.not recall how.
I found It useful to use the Wikipedia article on favicons.

I hope that helped