Well after searching for a template for a glass coffee/tea mug to try out something (frosted glass exterior and normal interior) I stumbled upon a winestein
My instant thought was that it would be interesting to model it, since it has to have a double glass structure, otherwise it would be hard to get the stem and base shape of the wine glass. Not to mention that if it was solid, it would be rather heavy.
So this is the rough shape I worked out for how it must look like internally
The green areas here are What I assume is glass, the grey is simply the surrounding air, and the red is the liquid. Not incredibly complex but a little mind bending when you have to make sure surfaces dont overlap and give you strange reflections/refractions because part of a layer suddenly thinks an glass/air interface is air glass. In all it was not as difficult as I thought.
I made a quick bench top model and added a few stock textures for bump mapping and this is the result.
[short time render longer one will follow]