Depending on your specific circumstances, Dan, I think you can get most of the way there with the where clause support for referenced items. Check out section 5.1.1 in the custom reports guide (Reports / Custom Reports on the ribbon bar) for details, but if you were to have three custom fields on your requirements - replaces, extends and includes - and put the appropriate requirement references in there, you could use something like the following to get the references you're looking for:
$listReferencedRequirements where RefLocation = Replaces
In addition to a where clause for the release you're reporting (e.g., $repeatRequirements where Release = 1.3), I think that should be about right. Give that a shot, and let us know how it works for your goals.