BPC,
Vadim's case was for you to do all of that in production. If you do that your transport landscape will not work going forward unless you bring back your newly created env\model into Dev. There is a debate on how to do that .. SAP recommends transports ... I have done UJBR before but you have to be careful and obviously you are on your own to fix issues.
If you want to keep the your transport landscape, the only way to do this is initiate it from DEV and promote it through your landscape... you will need to reload data either from the old source or dump your data out and reload it once the new model is in Prod.
I don't think there is an easy way ... I would probably create a new model in dev and cutover with data once the model is there ... then delete the old.
Akos