But when sensei has us do a technique thats extremely complicated, difficult, or very new to me, I try to find someone with a hakama or a brown belt, or who I know is more experienced than me so that I don't spend the entire time we have to work on the technique trying to figure out the first half of it.
Do you have anyone in your class who isn't as experienced as you are? Just a thought here -- not trying to be instigative, but how do you think they feel if they sit next to you during a class, see a complicated technique demonstrated, and you go work with someone who is more experienced than you are?
During regular training, I try to just work with whoever is sitting next to me. If there's something I didn't "get" during the class, I'll work with someone, perhaps the teacher, after class.
I think it all works out in the long run...