I've never understood why people don't try to find solutions for themselves, rather sitting idly with their thumbs up their butts waiting for someone else to come up with something.
First, I've found the lack of filterability of the 11-24 at the current time to not be a major, or even minor, concern. Clearly, we don't want to polarize a sky at 11mm. Even at 24mm, I wouldn't polarize the sky unless there was something blocking that portion of the sky that would be least filtered. However, yes, we often times do want to polarize the rocks on the ground, or the ocean at the bottom of the frame, or what have you. What I do in those cases is take the largest CP I have on me, and work my way through the portion of the image I need polarized, holding the CP in front of the lens and blocking stray light by using my hand above the filter/lens. Of course, my hand will be in the image, and so will the filter, but those are easy to mask out from the other images. You have to know how much light your filter absorbs, and then adjust your exposure by that amount when you're doing your CP shots, but this is a one time experiment that you do, and then you know it for the future. It's worked great for me, and the bonus is I don't have to carry a lot of extra weight and size of extra gear just for some shots.
I used to use a similar method when I was using the 14mm f2.8 for landscapes. I didn't want to buy a huge and weighty system. Not to mention, such a system does not fit in well with ultralight backpacking, as I would then have had to upgrade to a bigger bag, which weighed more, etc, but I digress. I had heard a lot of naysayers tell me how it would be awful to do my technique, I'd miss shots, whatever, I heard it all. I ran an experiment. During sunrise on day, I used a friend's Wonderpana system. During sunset, I used my CP technique. I also timed how long it took me to edit each image until it was ready as "one image" ready for actual post processing. For the ones where I used my technique, a smaller CP with multiple shots, this took a little longer because I had to mask in certain areas. Interestingly, if you look at overall time spent, it was actually quicker, on average, to use my technique over a "proper" much larger filter. The advantage is, less time is spent in the field, and you're sacrificing time at home spent on merging the images. I think we can all agree on that we have way more time at home available to us than we do out in the field. I'd rather spend my time in the field taking shots, then setting them up.
The one time I found the Wonderpana system faster was long after sunset, during twilight, when my exposures were so long that free holding a filter in front of a lens was simply too long and introduced too much movement. However, as you all know, there is little need for a polarized filter that late in the game. Even with a more "normal" focal length, like 35mm, during twilight there is no real use to using a polarized filter. There is not enough polarized light to make a drastic difference in your image. Try it. Take two shots during twilight. There will be some differences between a bare shot and one with a CP, but the difference is orders of magnitude smaller than comparable shots taken an hour earlier, or during much brighter times of the day.
