Oh man, that's so heart breaking. I'm so sorry you are going through this. I personally went through something "similar" with myself. I've been having chronic stomach pains...every time I would eat something my stomach would hurt so bad, I would either get nauseous and not be able to keep things down or I would have to eat very very small amounts and deal with the pain. I lost a ton of weight, and was very weak. After 8 months of medical tests, doctors finally found that I have lesions through out my GI tract which (if untreated) can lead to Gastric Cancer. Luckily for me, the biopsy results of the lesions were benign (but I'll have to keep getting them checked until they heal). I just wanted to tell you this because I've been through countless doctors and specialists and they all told me it was "nothing." I'm so sick of medical professionals not taking their jobs seriously and just being so lazy and careless towards their patiences. I'm sure Vets can be the same way...
Please DO NOT give up! As long as your dog is happy and active there is no reason to jeopardized her health any further unless matters call for it... I'm not sure what medical procedures they can do for a dog (without risking anesthesia), but demand every single test possible [within your financial limit]; blood tests, MRI, CT scan.... can they do an Endoscopy and Colonoscopy (technically you are not put completely under...)? X-rays will not show anything involving deep tissue (hence look into the MRI and CT scans), but an X-ray using Barium can detect blockages as well .
Is it possible to insert an IV and/or feeding tube? I like idea of feeding her that stew that someone previously posted. I would try that, but maybe not add all the ingredients at once...I would definitely hold off on the chicken skin for now though...if she's having an issue keeping things down, I would stay away from food containing a lot of fat and grease until she gets use to eating more. Plain yogurt and rice are great.... maybe find a protein supplement to add in to water you are feeding her.
There is also an organic honey that's suppose to have great medical benefits I'm not sure if honey is good for dogs, but it's called Raw Manuka Honey and it comes in different "medical levels." It is expensive, but I heard great things about it. I think the organic section in Wegmans actually carries a lower level of it...that many be something you would like to look into..
I wish you all the best of luck. I'll keep Lacy in my thoughts.
Please keep us updated. :|