What to do with a picky eater?

Ok, folks. I am stumped. Normally I always feel like I know just what to do when there is an issue with my child, however in this situation, where my son obviously has a mind of his own, I don't know what to do. Here's our situation: we have a picky eater. And not just a picker eater, he wont eat meat, either. He's a vegetarian...and not because we want him to be! Meat and potatoes would probably be one of my personal favorite meals, but not Landon. The doctor said he probably doesn't want the meat because of the texture, and I do agree with that, but even when we try and hide it, like putting very small pieces of chicken in his rice, he will eat around it and spit out the meat. The only exception is when we go to one of our favorite local Mexican restaurants, Rosie's. We order the deluxe blanco cheese dip (which comes with ground beef in it) and he will gobble it down, meat and all. So I am sure at this point you are wondering, well, what does he eat?

Here's a run down:
Yogurt - he could probably eat this 3 times a day without any complaints...
Banana's...actually pretty much any fruit except pineapple, and he prefers applesauce or baked apples to sliced apples.
Cheese of any kind with Ritz or Club Crackers (that's usually a snack food at our house)
Beans & Rice (and I usually put steamed carrots in his rice, and he will eat them, but he wont eat them unless they are in his rice...P.I.C.K.Y.)
Sweet Peas (some days yes, some days no - same for squash, too)
Granola Bars (I only give him the reduced sugar ones)
Mac & Cheese (however I must admit, he's getting tired of this one. It's touch and go some days)
Most all cereals - he really likes frosted mini wheat's and Fut Loomps (Fruit Loops)!
Pancakes
Biscuits - preferably with a touch of honey butter..haha!
Oatmeal
Strawberry Nutri-grain Bars
Raisins
Pasta - but only with Alfredo or Pesto sauce - he doesn't like tomato sauce on his pasta, however he does love homemade Salsa...but he calls that tomato sauce. Gosh, it's beginning to sound like he is part Mexican with the cheese dip, salsa, and rice&beans...eek!
He also loves mashed potatoes & sweet potatoes (though we think he may have developed a slight allergy to sweet potatoes, so we very rarely give this to him), most any kind of bread/rolls...yet he wont eat a grilled cheese sandwich (?) weird, I know.
Oh, and the one food he will almost always eat - Cheese Pizza.
He loves any and every kind of sweet thing available, (just look at the above header picture!) and I honestly try and bribe him to eat his dinner so he can have an oatmeal cookie...though most of the time it doesn't work!

I know there are some options here, and I am certain I have left some things that he likes out, but it just seems like there is no way he is getting all of the nutrients he needs. He wont eat eggs, and even though he once broke out in little red dots after eating a peanut, I did give peanut butter a whirl. He spit it out and said, "DON'T LIKE IT ANYMORE MOMMY!", so there is no way I feel that he is getting the adequate protein in his diet. He takes a Nemo gummy vitamin every night. His doctor always looks at him, and then looks at me when I go into a question craze in the office, and says, "Look at him. He's above average in every growth category. You must be doing something right. He's fine." And I am sure the doctor is right, and hopefully he will come around to eating meats and other yummy things like corn, salads, tomatoes, cucumbers (which I adore, and he wont get near them :(
Any suggestions for things we can try? Or am I just a worry wort? (that last question was rhetorical. :)