Even if there was gonna be a Prost-Senna teammate in the near future, i doubt we'd see Prost-Senna type of racing duel. The fact is, cars nowadays are so aerodynamic efficient and you won't get good aerodynamics while following the other car too near, unless of coz in a straightline. But in order to be close to a car in straight line, you need to be near him at the corners leading to it. So, unless rules on aerodynamics are changed soon, it'll be unlikely to see close battles in race tracks.
When Montoya signed for Mclaren, everyone was hoping for a Prost-Senna battle between him and Kimi as we all know how fiesty Montoya is. However, it has never happened and it does look like Montoya most of the time has lots of catching up to do. The closest team mate battles we've ever seen is mostly between Ralf Schumacher/Montoya, Ralf Schumacher/Jarno Trulli whereby they really would smack into each other to gain position.