I have been following this thread with interest- my now 14yo DS is very, very similar. We too had the gagging and barfing at the table when he was small, so much so that we backed off on forcing anything, just did a lot of (mostly unsuccessful) suggestion and modeling, cooking together, gardening, all that stuff.
I was about to write that things really improved as he got older- he is much more open to trying new things, though it is still uncommon that he actually likes them the first few times around. Eating with peers has definitely helped- he is on a team that likes to eat out, and they prefer Asian style restaurants- he has tried all sorts of things with his buddies that would never fly at home. And now that he's older, he has several vegetarian cookbooks and a couple on nutrition for vegetarians, as well as a few vegetarian friends at school, all of which have helped somewhat.
As I mentioned, I was about to say things improve, when I got to unpacking today's lunch- uneaten homemade pizza, uneaten homemade applesauce, water bottle untouched. He did manage to eat the berries and a fig bar and a yogurt- so that's a win in my book. Somehow he has managed to grow to 6 feet tall despite his limited choices, so I guess something is working.
Hang in there!