Well you certainly have your work cut out there.
I am thinking from your post you are talking about an all encompassing portable modeling station (as opposed to just a paint station)... some type of "omnistation"
The problem that you will immediately be presented with is that there are so many different processes involved in the construction and finishing of a model.
Different techniques, tools and materials will be used on each model on a by-model basis.
Different people use different techniques, therefore what suits one person will not suit another.
Another problem is the range of equipment used by model builders
Many of us have entire rooms dedicated to tools and materials we may need to use to create something smaller than a carton (sometimes a packet) of cigarettes.
Something to think about would be to create something that can be used depending on what stage of the build is being done. Eg...
a build station, (a tool box with a cutting mat)
a filter/ wash station (an absorbent mat with a mixing area and a shelf for materials)
a finishing station (a renewable paper base with a shelf for pastel chalks/ pigments etc.)
I'm not trying to put you off, but could you be a little more specific with exactly what you are trying to create?
Brett