I would be inclined to try the raw diet again. I know you have tried it before but it sounds like you had mixed other things in like veggies too. And not sure if you gave the proper time to a single meat source. Also were you feeding premade raw? Or did you do it on your own???
If I were you I would start with chicken meat and chicken backs/frames/carcasses. Do just that for a month or 2 and see how it goes. You'll have to eliminate all other things that your dog eats as well (such as treats and any type of vitamins or supplements that your giving). I don't give mine veggies (thats just me and there is a whole huge debate about that as some people do) but some dogs don't digest veggies very well.
See how your dog does on the chicken and then go from there.
Here are some sites on feeding raw:
Do as much research as possible about the raw diet. The more you learn the more you know and you will better be able to help your dog.
I suggest this because I went threw this myself first hand with Luke. He is allergic to all poultry and wheat, and he sufferred quite a bit before we discovered it. Alot of the vets were just medicating him with antibiotics and steroids. This really does just add to the problem more so than helped.
Another thing that I found with Luke is that he is allergic to all vaccines. We stopped vaccinating him as well. This was on recommendation by our vet actually about 4 years ago. This too is a very touchy subject and people have HUGE opinions and debates about it but I know it works for us and Luke has been so healthy ever since we stopped feeding him poultry and wheat and stopped his vaccines.