Hi Derek, the only thing that a component can carry in today's software is the material properties.
In 2014, components can carry some additional characteristics but not to the level that you're looking for. You're idea is a good one, but currently not possible. The closest that i've seen someone do is build an assembly with everything defined, use that as a template and then eliminate the things that aren't part of their simulation. So for example build a top level assy that will eventually be your enclosure. Drop your video card in there, setup all the properties for the video card. If the geometry changes, no problem. When you need to assemble an enclosure, drop the case in there, assemble the video card and you're ready to go. Follow the same process as the video card for other components.
I highly suggest submitting your "submodel" idea as an enhancement request in the solidworks KB. I think it would be pretty great.
Thanks for your reply. I have been searching around and submitting subcription services, now I know for sure it doesn't work.
Your comment is very educative, I think it is very helpful to me for my future usage of the tool. But I think for the case where there are serveal video cards (of course then we are not talking about deskptop anymore), it is still time consuming and not intelligent to assign the same properities one card after another. Also applies to the case when we want to adopt the same video card to another desktop with different components inside not just the enclosure. To have the properties attached to the model and be able to check it in to PDM (for wide range of users) is still the more intuitive way to buid simulation projects for D.O.E, I would think.