Sorry but 2000 your dreaming at least with a consumer router. A high end consumer router maxes out at 200 simultaneousness connections. Maybe one of those expensive CISCO routers might do better but why care unless your internet is ridiculously fast it would be a waste anyway with bit torrent. I have a DI-634M router that can handle 128 simultaneous connections and I am very happy with it.
You are wrong the 200 on the smallnebuilder "maximum simultaneous connections" means that it can support 200 wireless simultaneous connections. The number of ip ports the router can run is what matters and for that u need buffer space so that is what you really need for p2p.