I'd say you would still have an easier time creating the interface to edit the multiple products as if they were one than to try to get it actually working with variable options in a relational table.
If you did options and variable options then you would have to come up with a database structure that would allow you to store the inventory according to multiple options. A single option I could try to explain, but variable options like size and color, where each size/color combination has it's own inventory gets very complex from a database perspective.
You either need to add the complexity in the database or add it in the administrative interface. I'm just saying it would be easier to do with the admin interface if you aren't very skilled at this type of thing, and in that case you probably wouldn't have asked the question.
How would you create the admin for it? One page at a time... and each would have their challenges and would likely require at least some hand code.
Can you even imagine the interface you would like someone to use? I guess I would start with doing the design of what I would want to make functional and defining the admin experience. Then I would work on getting the forms to look right and function correctly before the form post.
Then I would get Webassist tools involved to do the database manipulation and form validation. But you are going to have to do a lot of work outside of the WebAssist tools to get it done either way.