Hi Jason. You are correct, this is an amazing support forum, one of the best (if not the best I've seen).
I don't believe that there is any way to search for users by workout. This would be an interesting feature though. I exercise with an elliptical most of the time, so it would be nice to find other users that do the same.
I also don't think there is any way to directly comment on a workout. You can leave comments on your homepage that other people will be able to see, but I don't think you can tie your comment to a specific workout.