Obviously cost can vary greatly depending on options chosen, but the quick answer is that proper custom wine racking normally costs between $12 and $19 per bottle of storage for an average size cellar.
So if you can find a person with the right combination of skills, you can have a cellar to be proud of for less than the cost of converted kitchen cabinets or the faddish metal systems.
***PLEASE NOTE: This was written in 2019. The cost of lumber has been volatile recently. Please call for current pricing: 612-501-2193