Opinions needed!

I'm thinking of doing a keezer spin off by basically making a lagering ferm chamber but having it meant for kegs. I was thinking of taking a mini fridge and building a custom chamber around it and filling all but the cavities needed for the kegs and for the circulation of cool air in the fridge with insulating foam. Has anyone done this or does anyone think this will be sufficient? Just trying to use what I already have instead of buying another freezer.