400mm IS

I have a Canon EF 400mm f/5.6 L USM. What I would really like to have is
this same lens with IS. At this point, the actual options (without
quintupling the price) are the Canon 100-400 IS, 300 f/4 IS + 1.4 TC and the
Sigma 80-400 IS. Sure, the 400 DO IS and 400 2.8 IS are available, but not
in my price range. So, what is the likelihood that a) Canon will come out
with an 400mm 5.6 IS replacement for my lens; b) a third party will make a
compatible 400mm f/5.6 IS/OS/VR non-zoom; or, c) someone will make an
IS/OS/VR teleconverter in Canon mount?

Second question: Has anyone made an actual comparison of the realistally
expectable photo quality between the 300 f/4 IS + 1.4TC, the 100-400 IS,
80-400 OS and the 400 f/5.6 L that takes into account the results obtainable
with IS? I'm not just talking about optical quality, but general sharpness
of photos in the real world, giving the lenses with IS/OS their due. I'm
starting to suspect that whatever marginal benefits the 400 f/5.6 L offers
in optical quality is outweighed by the benefits of IS/OS for certain
applications, like the small bird photography that I do.

The other option, is, I gues, using a gyroscopic stabilizer like the ones
offered by Kenyon Labs, but those aren't exactly cheap.

Eric Miller
www.dyesscreek.com