my name's Matthias Buehler, i am content manager at procedural, inc.
to get an idea about the current way to implement the cityengine in a game pipeline, check out the following show case:
this is a game which was created from scratch by a few students. the guy responsible for the level layout used the cityengine to create all building geometries. the assets of course were of course modeled in an other 3d application.
you guys are referring to a methodology to create models (in different LODs) directly from within a game ("realtime"), (without having to start the CE and export the models) by directly calling the cga shape grammar engine. this is currently not possible, but we have been asked about this many times already.
some of our current development goes in that direction, since one of our main focus is the game market.
the workflow so far is - of course - to create a pool of meshes in different LODs and load them in dynamically (proximity based, ..), as it's done in almost all games today.