I know its been a few months since this post was really active, but I thought seeing I had just built a series of Oracle Financials universe that I would put in my 2 cents worth.
Backgroud first. The reason that I created the universes was because we were retiring Oracle Discoverer which had End User Layers mapped over each functional area. GL, AP, FA, SOF, HR
I took a design approach of my customer who said they wanted to see all objects in one universe, but instead of building one universe, I built every one of these individually then created a Master Linked universe containing all the sub-ordinates. The Master universe then contains all the joins between the sub-ordinates and the contexts required and any generic dimensions like dates.
The universe has now been live for a couple of weeks and touch wood, there have been not issues from the customer perspective. I have one on a technical side, but I have put that in a different post and hope someone maybe able to answer this for me. You’ll find that post here
plessiusa 
(BOB member since 2004-03-22)