Unlike the IM niche which is virtually capable of having unlimited products to up-sell with, other niches seems to be just limited to a maximum of 2 (ex: PDF report + actual product). Well, aside from having your own niche membership site (which does not always fit in some niches) or breaking down your big report to mini-reports, stuff like that... are there other focused niches where in you can actually sell a lot of related products like the way it is in the IM niche?
PS. One niche I can think of at the moment that has at least 3 viable up-sells is: Bodybuilding, PDF Report > Health Supplements > Body Building Equipments. Any more ideas?