Im currently in the Coq Au Vin or Chicken Masala camps as well. When you said
you had ovens available at event site and wanted elegant, I was leaning toward
Chicken Cordon Bleu, ham-swiss-spinach-red--pepper stuffed. And using half size
hotel makes the breading process a lot faster, or it can be prepped and transported
then baked off at the event. HOWEVER..... looking back at that "800 guests"
made me reconsider that...unless you had a BATALLION of ovens at the gig site,
it might be kinda tough.
Hotel pans full of Marsala, Lemon Chicken, Chicken Alfredo or Coq Au Vin would be
far easier.