Just got news that the latest Canon 40mm F/2.8 STM lens will start shipping this Friday. For T4i owners, this STM lens is designed specifically for the Auto Focus feature of the T4i to be quiet and fast.
Canon EOS Rebel T4i DSLR Camera
I did not opt in for any lenses when I purchased the Canon EOS T4i, but I should be this pancake lens next week to see how usable the Auto Focus is. I was testing out the Touch Screen focus feature on the T4i with my other L lenses, and it seems to be fairly accurate. This new 40mm is listed as an EF (not EF-S) so it should be a decent focal length for both Full Frame and APS-C cameras. Available for Pre-Order now.
Canon 40mm F/2.8 STM Lens