I have a Pomeranian mixed breed dog( a mix of two separate classes of palms resulting in dog that is large for a palm, about 20 lbs) that has been diagnosed with a collapsing trachea. So far the vets do not seem to be able to help. Can anyone offer any information and/or suggestions to relieve the problem?

I'd think they could do constructive surgery

Collapsing Trachea is usually managed with medications-steroids, cough suppressants, and meds that dilate the airway.
Weight loss may be a part of the plan for treatment, it is also important for the dog to be in a smoke free environment.
Surgery isn't usually considered until all other treatment options have been unsuccessful.
This is not something that would be attempted at your regular vets' office, a specialty hospital or teaching hospital would be the only option if surgery were needed.
Here is some information on the disease.

Tracheal Collapse (http://www.marvistavet.com/html/body_tracheal_collapse.html)

Maybe use a harness to walk your dog instead of a collar so less pressure is put around its neck area.