I have posted on similar post; and asked on the companion Unity answer site, but as now there is no trace of a reply…and since i am an eternal optimistic, i am sure that here i will maybe get enough visibility to deserve a reply 
This is the scenario: Xcode, nice, lovely, with all the nice components to add to the nib file…now picture that: you wanna do something in a program that imply an output to render an object…easy to do until you wanna render the object, since OGL is one of the most painful things that you could potentially learn…enter Unity!
instead of having a window that loads the OGL View; would be nice to have Unity to do the dirty work; but i cannot find any reasonable way to create a nib file with my UI, and then add a square on the corner of my app to run Unity in it and render the results of the manipulations on a real time created mesh (basically do something that i cannot describe, get a mesh from this operation, render it; change parameters, render again and so on).
I know that Unity is not an add on for Xcode (and btw this is a desktop project, not an iphone), but i wonder if there is a way to let it talk with xcode, being the delegate for the render window instead of using Ogre or OGL or god knows what else…
Now if this is not possible would be cool to know; so i just put aside Unity for now and pull out of the collector’s box the old version of Irrlicht; otherwise any suggestion about how to achieve this would be appreciated
And before you ask: No, i cannot use the GUI from inside Unity, since i must have a totally “Apple look based” application, and the 3d render is just a marginal part of the app; tried to do everything with Unity and the skins and is not the same 
If i don’t get a reply i will just go depress myself watching the last airbender and A-team 