Modified 6 Dec 2012: One approach to this question is to perform a sequence similarity search for genes encoding genes with a functioning in sensing external stimuli, be they
olfactory receptor, taste receptor or other such genes that are expressed in cDNAs or RNA-Seq data from library preparations of the appropriate ear tissue. While there is not likely at this point in time to be much data available in RNA-Seq format, one might find cDNA libraries from cochlea or neighboring tissue.
A "hit," meaning there is evidence that, for example, an olfactory receptor gene is expressed in cochlea, eg, only means that there is potential to smell through the ears. Taste receptors are expressed throughout the alimentary canal in humans, but tasting the contents - food or other - is not readily perceived as de facto taste outside the oral cavity. Nonetheless, there is no reason not to expect such sensors are expressed to relay information to the brain as to what is or is not present. "Smelling" in/by the ear for the purpose of detecting the presence of a given entity or molecule could serve a similar function.