Coming out of lurking here. Ha. I found these you can get in singles or cases of 36 or 72. They have lids available too:
http://www.barproducts.com/barconicr-2-oz-mini-mason-jar-shot-glass-13599
http://www.barproducts.com/barconicr-2-oz-mini-mason-jar-shot-glass-case-of-36-fsp