More than one column? Well most likely not. The listbox is windowless, meaning everything it does is defined by a function in the Messenger files. (it is possible in C++ to write a header file for this and use the controls, but I don't know how
its complicated). Since this is not used anywhere in Messenger, it is likely that there is no function to make the listbox have multiple columns.
Even if there was, this would be a very big project...and also, how are you going to be able to see contact info on multiple lines? the icon, nickname, and psm usually take up a whole line (unless you disable PSMs)...