KeefyB rightly pointed out the correct site link I was thinking of.
The 999 workshop manual is 24Mb - why? - probably because it includes loads of colour photos of the work taking place - kind of Haynes manual type.
The 749 - I haven't seen the workshop manual but the link (on that same site) which says Explosie tekening 749(8MB) is the engine exploded parts diagrams for the 749. Don't be put off by the Dutch(?) file name, the Ducati lists are given in four or five different languages on each page-including English.
The user manuals - still available on ducati.com - the entrance to ducati.com may be down but this link still works:
http://www.ducati.com/bikes/manuals