it is well-known that there are many extremely long straw stalactites found all over the world (what is claimed to be the longest?), but has anyone calculated the maximum possible length of such a straw, for a given diameter?

The calculation would have to assume that the limiting factor would be the strength of the straw itself, ie that it was bonded sufficiently strongly to the ceiling. If the calculation hasn't already been done, do any of you have numbers for the density and tensile strength of calcite?