My 2 and a half year old GSD is coming on really well in Obedience and our instructor thinks we are ready to trial except for one SLIGHT problem.........................He cannot will not let me out of his sight...stays-forget it! If he can see me he will STAY like a dream for ten minutes at least but if he can't see me, he cries, screams, tries to get to me and spins like a dervish, I had hoped that giving him a rock-solid stay would overpower his need to see me but No.

Ideas please?

Brooke, your doing better than i 10 mintues is good, my 2yr female all most died when i had a heart attack,i was gone for 10 days she did not eat and howled the whole time, the neighbors call the police, after all the excitment and i was home she has not left my side for a mintue and she was tracking out of sight,so anything can cause separation problem ,maybe working with a tracking dog and trainer if your club has one will work or there is alot of trainers here and maybe they will have advise. The only time sepsration has worked is when i breed her and that was only as long as she could hear me

It will be very easy to fix...It will take about a thousand repetitions of you leaving his sight for a very short time and gradually increasing the time until he is comfortable with you being out of his sight for 10 min or more. If you go slowly enough he will trust that you will reappear and will stay relaxed.
Tie him near a big pillar or anything just wide enough to hide you, like a SCH blind. Walk a path that takes you behind the pillar and do not stop behind it, just keep the same pace. If he gets antsy from that split second repeat it until he is calm. Then do it again but walk slower so that you are behind the pillar for slightly longer. When he is comfortable with that, pause very briefly the next time. Keep doing this while gradually increasing your time out of sight. Be sure to do the exercise in different locations with gradually increasing barrier sizes. If he gets uptight go back to the last step where he was comfortable. If you go slowly enough (break it into baby steps) you can get him over this. Make sure you wear good shoes (because you will be doing a lot of it) and always end the lesson on a relaxed moment.
Does he do the same thing at home?
That would be a good place to start the lessons and then move to the new places, but expect relapses every time you go to a new place.