If I dynamically create scene my 3D scene in unity, (a drag and drop kitchen for example)
Is it possible to output that scene, in a 'standard' 3d model format, at runtime for further processing, such as import into a virtual reality system.
Yes, use the ObjExporter script on the wiki.
I don't think there is a built in function for that, but if you have some experience with 3D-Models and are familiar with some of the "standard" formats you could write an exporter yourself by accessing the data of your meshes and using standard c# file writing.
As I said, that is what i THINK. Maybe there's a quicker way to do this, that I just don't know of.
you should get the data from mesh filters yourself and then convert them to the format that you want. i think you can find SDKs that get data from you and convert them to formats like COLLADA or FBX. the formats are not complex. you can do that yourself too.