Very interesting discussion here. I'll just say a few things here to point out that there are different schools of thought in organ design and organ playing. Giovanni's remarks reflect his admirable love of Cavaille-Coll instruments. I admire these kinds of instruments as well, but I also have great admiration for instruments in the German Baroque style, and also in 19th century American style, such as Hook and Hastings.
To me, a large-mid sized instrument is three manuals and has about 35-40 ranks. I consider 50 or more stops to be a large instrument, and I can be quite happy with a 2 manual instrument of about 25 ranks, if they are well chosen and nicely voiced. In my opinion, you are better served by learning to combine stops on a smaller pipe organ than using any kind of electronic organ because even in the best electronic instruments, the stops do not combine the same way as they do an a real pipe organ.
However, I do agree that there are times when an electronic 32' works ok. The lower the sound, the more successful an electronic substitute is, and if you're adding just one electronic stop, you don't have the blending problem of more electronic stops. However, that being said, I am on the conservative side with this. I think there are many organs with electronic 32's that seem ridiculous because of the size of the room they are in. A good 32' is a nice sound, but it is not in any way necessary for playing ANY repertoire I can think of. I have played lots and lots of very satisfying instruments with no 32' at all. They should be reserved for rooms large enough and instruments that would have a real one if it could be afforded.
Some resultants work very well, however I'd point out that when the quint is taken from the same rank, it is rarely successful. To make the perfect blend, the pipes must be tuned REALLY in tune, not tempered as in equal temperament. This can only be accomplished with a separate rank. To my ears, all borrowed mutation ranks sound awful. It is just not possible to make them work sucessfully because they cannot be tuned correctly.