Re: My Idea
One of the issues is that when dry ice is added to water it evaporates and makes carbon dioxide and rapidly expands. This would cause everything you were breathing to be CO2 and that is deadly. The pressure inside the base would be positive and therefor the hose would always be blowing out and you could not actually draw from the stem. If it is outside the vase then you will be filling the are that you are smoking in with CO2 and that is dangerous too.
One other point is that once you chill the smoke that much you really hurt the flavor. Cooler smoke is nice but at a sacrifice of quality of flavor.