I have seen other forums that have a "banned member" title for those who aren't welcome back. The idea of linking to the thread in which they were banned would most likely significantly increase complexity of the software, and if this happens at all, I would be almost certain that that wouldn't (and it doesn't matter to me anyway, seems like a not-terribly-useful feature - if you really have got to know, search with their username for the last few threads that they posted).
On banned vs. vacation, I thought that a vacation was a ban which the mods made a mental note for themselves to unban you x number of weeks later. So how would the software differentiate between bans and vacations?