(((hugs))) That must be really frustrating!!! I think it's important to keep in mind that if you are feeling stress with regard to mealtimes, then I'd bet your ds is too. Kids that age, they have just 2 things they are in complete control of....what goes IN (food) and what comes OUT (potty)....so it's no wonder that these are the 2 biggest power struggles with los!!!
IMO I wouldn't bribe, force or cajole, as that is exhausting for both of you, adds to the stress and anxiety, and you run the risk of making it even more of a power struggle, kwim? I would just keep offering and not talk much about it. I'd put 3 things on his plate, one thing you KNOW he'll eat, one thing he sometimes will eat, and a new thing. As hard as it is to accept, he won't starve if he dictates his diet...just keep his choices as healthy as you can!
Look at what he eats in a week, not a day, and you might find that it isn't that bad!! If his diet is very limited, try expanding it along similar lines....for instance if he likes toast, offer him french toast (you can put it into the toaster after cooking to give it a more similar crunch). Also, presentation is key at that age...try cutting his snadwhiches into strips, or making them on crackers instead of bread....better yet give him the meat and cheese and crackers and let him construct his own lunch!! Dips are a great way to make food fun and more interesting too.