The unit you have is not designed to be that cold. If you were able to adapt another thermostat to the unit it would only cause premature failure of the compressor and related componants.
In addition to the added strain of the lower temprature there is also the fact that these units were not designed for constant use. What I mean by constant use is a wine cooler is not opened up all that much, where a regular refrigerator is. This again will put an added strain on the system.
My suggestion to you would be to use a regular refrigerator unit rather than the wine cooler for your beverages. Modifying the unit you have may be possible but if you did locate a matching thermostat I will guarentee you the unit will not last through next summer.
If you are determined to do this the best shot you have of matching a thermostat to the existing unit would be to contact the manufacturer directly. They of course will probably tell you the same thing I am and not advise you on an alternate thermostat due to liability issues.
As for myself providing this information it would be difficut to say the least. If I had the full set of manufacturers numbers with cross refrences then it would be possible. Unfortunatly the only people that do are the manufacturers and they are holding it as propriatary.
You might try contacting your local appliance center. They may be able to cross refrence this information for you but again I do not think they will due, again to liability issues.
I am sorry that I can not provide you with something more proactive than what I have. If for some reason the diffrent thermostat caused a fire, or something else unforseen, then the entity that provided it could be in some seriously deep doggy doo doo.
I am sure that this is not what you wanted to hear, but it is the only honest answer there is. I, unfortunatly have no control over some of the answers that I must give.
I would appreciate it if you would honor the time I have put into researching, and answering your question by clicking on the accept button.
Best regards; The Home Smithy