From my experience playing accoutic guitars (I know, completely off base), that cigarette smoke in a sense oils the wood for you and, even though it may smell bad, guitars in cigarette smoke filled environments seem to age better than those not in like environments.
This being know, it is possible the tar from the cigarettes have seeped deep into your cab's wood. So you have a few choices, try to mask the smell, replace the wood, or try to get another oily substance into the wood to counteract the smell of the tar. Masking the smell seems like a feasible option considering you do not need any bare wood, but finding a way to introduce new oils to the wood might be a better, long-term (forever) plan. The problem I see is will likely not want to rub oil on your cab (because you are dealing with a painted surface), but introduce the oil in the same way the cigarette tar was introduced, via smoke or air. This being said, the cedar chips might be a good idea as they emit an oily odor (they also work to get rid of moths) or moth balls (I prefer the cigarette smoke smell to moth balls) or something that emits an oily, pleasant odor. I cannot think of any products off the top of my head, but many plants naturally emit this sort of odor (pine trees, etc). So maybe get some cedar chips (a lot of cedar chips) and put them in a coffee can with holes in the sides in your cab. Remember, if the cedar smell stops coming from the cedar chips, you just need to break them apart or sand them down (if you are using blocks) to release more of the smell.
NoBonus