Diet for sensitive stomach?

But the thing is, I *have* given him a purely kibble diet and given him time to adjust to it

 
  Sorry; I must have misread your OP. I hope you figure this out.

Forgive me if any of this has been mentioned or if I missed something, but I take it that your dog has been to a vet to rule out any sort of intestinal problems??

If that is the case, you could always just keep trying different kibbles (I would try California Natural Lamb) and add fish oil/vitamin E supplement.  As far as the tartar goes, you may just have to brush your dog's teeth more often...you may have to do more "maintenence" on a kibble diet as far as dental health, but from what it sounds I think it worth it and it outweighs the other problem....

Willowchow, I'd like to try Natural Balance. I don't have a Petco here, just a Petsmart, a Petland, and a couple of local stores, but I'll see how close the nearest petco is to here, or see if I can find a supplier in my area.
 
 
 

Forgive me if any of this has been mentioned or if I missed something, but I take it that your dog has been to a vet to rule out any sort of intestinal problems??

 
Well, no, he hasn't...because to me it's fairly obvious that this is being caused strictly by diet. I could be wrong, but if it were some kind of intestinal problem, would it still go away, like it does now, when he's switched to kibble? Wouldn't he just have upset in general? Again, I could be wrong, but that's just what I'm assuming. [&:] Is it really necessary to take him in if changing his diet helps? Taking him to the vet is quite an ordeal because he has some fear issues (which we're working on) and if I can figure this out without taking him to a strange scary place I would like to. If I thought it were something really dire I would take him in a heartbeat...but to me, it just seems like he gets an upset tummy on certain foods, and all I really need to do is mess with his diet until I find out what he's okay on.
 
 

I do understand where you are coming from, but if it was my dog I would take him just to be safe.  That way at least I know that it is the diet.  It could be some type of colitis, or a bacterial infection that may act up when being fed a certain food (raw for example).  

Could be giardia too.  Its notorious for causing intermittant runs, picky eating & difficulty holding weight.