That's a good deal, especially on the trade in considering $22k is more than about any 6.0 is worth unless it's been studded and egr/cooler delete. (Just had a buddy's stock 06 6.0 with 75k mi on it pop the head gasket last week, just starting it in the driveway. Now he's got a payment on a 7500lb paperweight waiting on a $4-5k repair for just turning the key. )
$10k off of a new one that you ordered seems good too.
I'd be happy with that deal all around.
Did you offer the new owner your condolences in advance? God I hope the dlr didn't make much off the sale or he rally got taken.