I like that you are thinking "out of the box" to find what works best for YOUR dog. Years ago, with our first Ridgeback, we were told they needed a "rough" diet (i.e. cheap-o dog food). She ate it, seemed to like it, kept weight OK... but she pooped 7 times a day! So we moved up the feeding quality scale.
I like a nice, basic kibble, but there are varieties. My dogs go on a chicken-based kibble, so I can easily switch between brands if traveling. Our breed tends to not do well on a richer meat, such as lamb, but you may find your dog has a preference for one meat over another. Chicken, Beef, Lamb, Fish are all pretty common, & have different flavors.
Look for the middle of the road brands @ a local pet shop (either independent or chain). I have fed Nutro, Royal Canin & Eukanuba, both of which I believe are national brands. In the midwest, we have Fromms & American Natural Premium, which are locally made & may not be available where you are. This way, you can keep costs down, but also have a variety of tastes/textures that might appeal to your dog.
We mix our kibble with water, so that our dogs don't choke, since they feed like a game of Hungry Hungry Hippos, but it also brings out the scent/flavor, so that might help. Also, feed very small meals, but often. That way, you aren't throwing out an entire meal if not eaten.
If you do not have luck with some of the varieties, I would recommend going with a grocery-brand food. There is concern regarding contamination, so be aware & stay on top of recalls. I would start with Pedigree, it is a basic chicken/corn product, nice & greasy. Purina One is also a good choice. I've also read good reviews on Costco brand food, if you are a member.
If kibble just isn't working, consider switching to a raw diet. It takes more preparation/storage on your part, although you can get pre-made packages (they are significantly more costly than buying bulk chicken, etc. & making your own). It is more than just tossing raw meat to the dog, however, you need to make sure the diet is balanced with other foods, such as vegetables.
Finally, I am attaching a link for Satin Balls, which is a complete-food recipe for dogs. We've used this when our dogs are sick & go off their food - you can make marble sized balls & force feed if necessary to keep energy on a dog that is going downhill. But it can also be fed in larger sizes for the dog to consume on their own.
Best of luck, I hope something works! T. :)
http://www.instructables.com/id/Put-weight-on-your-dog-wi...