Any idea if it's possible to create a barrel vault skylight that would work similar to a curtain wall (i.e. stretch the skylight and it adjusts to a fixed size and adds mullions)?
Use a curtain wall then. drawn as an arc.
Then rotate it in 3D.
You would then need to fiddle with the display manager to get the CW to display rotated.
I would copy the Model display rename it Model4Plan or like, and tick it to on but turn everything off. This keeps things as they are. If you then edit any CW in plan view, you would see 2 bold entrys the Model4Plan should have everything turned off.
You would then override the Roof Vault style and turn the normal plan view off and model4Plan views on.
Well at least that's how I've done it.