A thought: Making a EF 28-90 f/2.8 IS USM

I am guilty of much lens hackery, see these pictures for the explanation in a nutshell (NO, these are not PhotoChopped.. this time it's real)

And I was thinking, it might actually be possible to CREATE an EF 28-90 f/2.8 IS USM. Let me explain. Initially this lens was slammed, but I've always realized that there is no functional equivalent in EF land. Not if you want f/2.8 and IS, so that's a healthy serving of cake and the ability to eat it too. Let's not go into "how useful is IS" - some of us want it, and we will go and get it.

There's enough mirror clearance on a 1D to allow me to mount and use the 17-85 lens at all focal lengths. However, there is a small vignetting problem:


Of course one can get around this problem by cropping. It so happens, for maximum image size without the vignetting, you'll apply a 1.6X crop in software, thus the lens will yield the equivalent of a 28-90. Regardless of the 1.3X, 1.6X or FF camera you mount it on.


So....has anybody tried doing the EF conversion of a 17-55 f/2.8 IS USM? I don't have one or believe me I would try.