Well, one thing that would help would be for you to upgrade to 2010. There have been many advancements in the 3D environment since 2004 and the new tools and techniques available would really help speed up your workflow.
Another thing that would help, and maybe you are already doing this, but having a library of pre-made pieces that you can re-use over and over again is very important. You talked about the mouldings you make. Are you saving those out so that you can use them again on other models or do you start from scratch every time? Having a good library would allow you to slap these models together very quickly.