is it possible to make shipyards act like the ship upgrade station(when a tech level is reached a ship is replaced by a different one) or not if so how would you do it
I don't think that can be done with A2. A1 it can be. The reason behind it, is you can't get the same object to use more than one class label. Almost every attempt to use more than one classlabe results in a crash.
It may be possible with some clever techtree and odf editting .....
Paul's right. Almost anything is possible, if you're clever enough. However, the result will probably not be exactly what you expect. But you can usually get it reasonably close to what you want.