Maddissun - something that has worked with my DS is where we live, there is a fruit and vegie shop that has little trollies for the kids to push. DS absolutely loves pushing the trolley and picking the vegies and putting them into bags and then into the trolley. When we eat tea, I point to things and say "Tom got that from the fruit shop like a big boy' and it is amazing what he will eat since we have been shopping there. Broccoli, corn, capsicum, beans etc . I also admit to cheating and he eats things that don't actually come from the fruit shop even though I tell him they do.. He is super fussy too. (I even have to send a sandwich to daycare because he rarely eats their meals - argghhhh!!).
I have a recipe for 'healthy' sausages which is just basically a way of hiding vegies in meat and calling it a sausage if you want me to pm it to you. DS would live on sausages if he could..