First off, I'd have to agree with PAOLO. Serving a shot in a plastic glass
sucks. The presentation is horriblem, it doesn't have that heavy, solid
feeling to it when you throw it back, and plastic usually has a funny
taste/smell to it. But as you said, you're breaking 25 glasses a night. Here
is a link to a place that sells plastic stuff, including shot glasses. At an
extra charge, you can even put your bar/club's name on them.
http://longshotz.com/shooters.html