You might try pec deck flys. On a pec deck that has the resistence on the point of the elbows, rather than on handles that you would grip with the hands. One of the main functions of the pecs is to crossover the arms in front of the body. With the resistence on the elbows, better leverage on the upper/lower pec's is produced. Keep the elbows a little higher than shoulder level throughout the exercise.
Can also try cable crossovers but keep a bend in the elbows, the closest to 90 dergrre as you can. Again keeping the elbows level or a little higher than the shoulders. Flat, incline or decline DB fly's are not that effected in building the pec's for a lot of the muscle tension is reduced (or lost) when approaching the top half position.
I have a friend of mine (6'2...265lbs) with a hugh rib box and chest except that the upper pec's look flat as a pancake. Comes to the point that nothing seems to work on that area no matter what he try's. And he has the oppoutunity to workout at some top of the line hardcore BB'ing and lifting gyms around SoCal. Say's his father and brother have the same problem. His triceps and anterior delts are huge, moreso than a lot of Pro's but no upper pecs at all. Not saying this might be Brix Dog's problem but just as an example of how some genetics can really be a bitch for a few people. You usually can overcome a lot of bad genetics with a little planning, but sometime you have to deal with the cards your were delt. Good Luck.
