I found these great glass displays on Craigslist. Although I had to drive for an hour to pick them up, the seller did throw in a couple of "bonus" display units too. The two large displays are from IKEA (Detolf model), and retail for $95.00 each with the overhead lighting.
The two small displays are also from IKEA and are a discontinued item. The seller stated that he paid $60.00 each for the small ones new and had the locks installed at an additional $12.00 a piece.
There's not a scratch on any of them. This person took extremely good care of these display units. By doing my shopping on Craigslist, I managed to get all four display cases for $100.00 total, saving approximately $261.50 off of the retail price (including tax). These displays will be a great addition to the new store front!