You wouldn't need to invoke the idea of 'hormone resistance' because TSH and T4 tests normally used to diagnose hypothyroidism don't measure the active hormone - T3. T4 is just a prohormone with very little direct activity on metabolic rate.

In primates, metabolism is regulated primarily in the liver by T4->T3 conversion, so if this is inhibited for any reason it will suppress metabolism without showing up on those tests. Low calorie intake, and poor nutrition are known to cause this (e.g. Euthyroid sick syndrome). In cases of poor liver conversion, supplementing T4 can actually make symptoms worse, as it will further suppress metabolism by lowering the small amount of T3 production from the thyroid (via the TSH feedback loop).

I assume you have heard of Ray Peat? I personally had good luck applying his ideas to increase my energy levels, and my pulse, body temperature, and cold tolerance raised as well - without supplementing thyroid. His general idea is pretty simple- just look at what conditions and nutrients maximize T4->T3 conversion, and provide them (low stress, high nutrient diet).

Broda Barnes work is very interesting. It blows my mind that he published a paper in The Lancet showing that desiccated thyroid lowered cholesterol levels and seemed to prevent cardiovascular disease in his patients, and that it remains virtually un-discussed and uncited (http://www.ncbi.nlm.nih.gov/pubmed/13796871).