Upload & Sell: On
The Oly 21/3.5 and CV 20/3.5 SL-II that I referenced are both FF lenses (that can be adapted or are native mount for Canon EF), so pancakes in this range are definitely possible (though pushing up against design limitations for the reasons Gochugogi mentioned). A 14mm lens along these lines might just be possible for EF-s (assuming mirror clearance is scaled proportionally with the 1.6x crop --- what's the actual mirror clearance on EF-s?), though not for FF.
I'm not familiar with Olympus system, so I thought it was for a four-third system. Sorry for the mistake. Still, that lens is pretty thick. Now, I wonder how "thin" of a lens to qualify as a pancake lens.
The instant rebate suggests the EF40 2.8 may go up to $199 in January. Guess its time to buy Christmas present for myself.
And Canon just might extend it again.
IMO this lens is worth every penny at $200, and is an absolute steal at $150. treat yourself