Theoretiocally there is no limit on bookmarks nor on number of pages. I created an 1100 page pdf (all pictures) yesterday with no problem.
When you create a big pdf with a lot of info in it you do have to keep load time and page dislpaly time in mind. On and older slower computer, with little vram and/or no video card, display and page advance of a huge pdf can become very slow.
Using OSX 10.3.9 on a G4