I've been lurking on your thread for a while, but wanted to actually post and say I'm so sorry that you and little Zeke are going through so much trouble. I lost one of my beardie girls Monster few weeks ago due to sudden heart failure and my other beardie girl Lotus was pretty sick for the past week as well. So I understand what it's like to be worried to death, and I feel for you. Zeke definitely seems like a fighter though, and if it's at all possible for him to pull through this then I'm sure he will! You are certainly doing everything right for him.
Can your vet do another ultrasound to check for obstructions or swelling in his intestines/stomach which could be causing the vomiting? He could also check the "movement" of Zeke's digestive system to make sure everything is going in the right direction. My Lotus was having vomiting issues as well (you can read her thread here if you want >>>
viewtopic.php?f=45&t=172680). When my vet did the ultrasound he found that the movement of her digestive system was kind of rocking back and forth instead of moving towards her rear end like it should. My vet prescribed a medication called Metoclopramide. It's not very commonly used in reptiles from what I understand, but it definitely seemed to help my dragon's digestive tract move in the right direction. Maybe you could ask Tracie and your vet if something like that could possibly help Zeke with the vomiting issues. There are some possible side effects, but it seems to be generally pretty easy on the system - it seemed to help Lotus feel better & there was no loss of appetite or anything like that.
I personally use a Critical/Carnivore Care mix from
http://www.beardeddragon.co. It's 2/3 Critcal Care and 1/3 Carnivore Care so it more closely mimics the nutritional proportions of 80% veggies/20% live feeders that a beardie's diet should actually be as if they were eating normally. The Carnivore Care is obviously heavier on the protein - and while protein is good, too much of it is not. Too much protein over an extended period of time can potentially cause organ function issues and elevated uric acid levels, which my dragon also suffers from due to her previous care before I rescued her. You could get some Critical Care and mix it yourself too. I'm no expert, but I remember AHBD telling me that Critical/Carnivore Care is pretty rich for a weak & empty digestive system. Lotus has vomited straight undigested Critical/Carnivore Care before as well. Now I mix mine now with 1 equal part veggie babyfood & 2 parts water, and she's been keeping it down for almost a full week.
Anyway, I don't mean to talk so much about my own dragon - I was just hoping that her recent struggles could maybe help your little Zeke get through his. I think what started Lotus's whole vomiting ordeal may have been related to her temps being just a tad too low to digest food. I know it's a really simple thing, but have you checked his temps recently? Sometimes the simplest things can go overlooked when you're facing issues so much bigger.
I do hope your little guy is feeling at least a bit better now. You're doing such an admirable job with him - he's very lucky to have you as a beardie parent! I'll be hoping for your sweet dragon boy to pull through.