Yeah, the problem comes when two apps attempt to grab the same port. One app can listen on one port and then filter the incoming data to different worker threads so that it has numerous functions being handled by one port (webservers and name-based hosting come to mind).
As for the question about remote DOS windows - no need to write your own, mate. RCMD has been around since NT 3.51, and is free for download from MS as part of the publically available resource kit. Not too hard to slip it into something else, too, as it's small and lightweight...
I can tell I've got alot to learn from you guys. I've been fending off hackers for years, without ever programming. I know alot about the tools and processes you guys utilize, and about the exploits that your custom code exploits, but I'm just now taking my first baby steps into writing my own stuff. Keep on posting good information! I'm learnign alot.