I include clipping paths with about 80% of my photo submissions. I also include that the photo is "isolated with a clipping path" in the title, and the description field.

I just got a note, from someone at Dreamstime, that clipping paths are only included in the largest size. That kind of makes my description misleading, and I intend to reword my descriptions to note that.

My question is what other sites (of the top eight) eliminate clipping paths for all but the largest size?

iStock.

I think 123RF too.
One time I was not on my comp and dl free my file from 123 to resubmit it on iStock because of few bad keywords and this file dont have clipping path.

You can upload an .eps file with the embedded clipping path as an "additional format" on DT to insure that there is one option that is guaranteed to have a clipping path. I've done so on one image as a test and get downloads. Since you already have the path created it is easy to save it as an .eps and upload it - one more chance for a download at a higher price. Just put a note when uploading as to what it is and why you are uploading it in case you get a reviewer who isn't familiar with this type of .eps. Then put a note in the images with this additional format saying something like - ".eps format includes clipping path." Savvy designers will know what that means and want that option.