My little dragon D has had the same problem. He's a pet store purchase, and so came with a lot of problems to begin with (kinky toes, -really- nasty parasites etc) We got the vet to check him out, got rid of the parasites and for a while he was great, then, after his first brumation, he just never got his appetite back. He got really lethargic and kinda just laid aorund most of the day, up on his stick, watching people, didn't touch his worms, and it was all I could do to shove greens down his throat.
The one thing he would eat, with out problem, were horn worms. He'd even let waxies go by, but hornworms were gone in a flash. Now, hornworms are bloody expensive, and as much as I love my baby, he's not going to eat gourmet food just because he's a picky little bastard, especially when the vet checks him all out and says his perfectly heathy. So this is what I did:
I bought a hand blender. One of those little portable blenders usually made for using smoothies? It cost me $30. Into the hand blender I tossed his veggies, his calcium, his vitamins, his worms, some baby food, some jump start and water to keep the mixture liquidy and set the whole thing to mushify. I had to experament a little with different kinds of syringes to use because the stubborn bastard kept biting the tips off, but if you can get your vet to give you a decent supply of some bigger ones, they work best. Then, it was just a matter of getting it to him. I found that leaning against a bed or a couch and brining my knees up, having him facing away from my on my thigh was the best position. Now, you'll probably want to find your own comfort zone for this, but here's what worked best for me:
1) Cup his head in whatever hand isn't your writing hand (lets assume you're right handed, so you'll be using the left for this) with your thumb resting on the top. You're going to want your most dexterous hand working the syringe. He's going to try and pull away and will probably move backwards, but since he's facing away from you on a slope, he'll only trap himself closer to you.
2) With your left index or middle finger, gently pull down his bottom bottom lip on the right side, near the corner, as though you want to get a look at his teeth. He wont like this either, but tough cookies, he's gotta eat something. Just remember to be gentle and patient. It might take a couple of times for both of you to get used to this.
3) Fit the tip of the syringe between his two lips. Don't try and force it past his teeth!
4) Carefully slide the syringe around to the front. Be careful not to press inward too hard, or you might hurt him. His natural reaction will be to open up as the tip of the syringe comes closer and closer to the front. When he does this, be ninja and pop the syringe in and squirt in as much goop as you can before he flails away, just make sure you don't drown him doing so.
5) Give him some time to recover and glare at you, then repeat, until he's taken at least a syringe worth.
It's time consuming and tricky and frustrating, but it's a better alternative than watching him starve himself.
Oh, and in case you're wondering, yes, I do make smoothies with the same hand mixer X3