>we deal with similar design here and the approach we use is to have multiple select statements in sprocs and readers to populate collections etc.

Maybe I was fragmenting the flow too much.

Sticking with my example, when would you load the different entities?

Let's say we are going to bring up an alphabetical list of vendors, and we are going to click on the vendor and "zoom in" on their PO history. Are you going to load all vendors, their POs, and all line items once? Or are you going to load a list of vendors and later load a certain vendor's POs when they are zoomed in on?