How create a smart playlist that shows only full albums in my library?
There is no way to automate this functionality in iTunes today.  To do so, the system would need to know how many songs were in each album and that isn't immediately available.  Plus, what if you have an album with twelve songs and you only have eleven, but you still want it in the list.  Or what about singles that have only one or two songs.  Are these "complete" albums?

In any case, the only way I know to do this is to mark complete albums manually.

For example, you could put a note in "Comments" like "CompleteAlbum" and build a playlist for all files with Comments that contain "CompleteAlbum".  If you want to stay out of the comments, you could use the Disc X of Y, clearing the Disc # for non-album tracks and setting it to 1 (or 2 or whatever) for albums.  Then, you build a playlist that looks for songs with Disc # >= 1.  It's up to you.

You just have to remember to do that for each album you add, but your playlist would contain all your 'complete albums'.