Dynamic Dependent Dropdowns possible without naming ranges?

Hi,
I've spent hours looking for a solution to do what I want to do, first in google spreadsheets and now in excel. I can't find any example that allows me to do this simply and effectively.

Basically I want to be able to let other people input inventory items without having to type in much of anything. The items would be based on a list in another sheet. This way, all the models stay exactly the same and I can count them easily.

I want to avoid having to name ranges so that any common joe can add items to the list to choose from easily. It seems if I want to use the Offset and Indirect methods I would have to do this. Maybe ArrayFormula could be of some help?

Another sticking point is I'd like to be able to filter this list and sort it in any manner imaginable without screwing up previously inputted data.

I've attached a spreadsheet that outlines how I'd like things set up, hoping that someone knows how to make this up with much less headache than it's given me!
Thanks!
Kevin

Here are some other links I've tried and failed:
http://www.excelforum.com/excel-prog...rop-menus.html
http://www.excelforum.com/excel-gene...own-lists.html <<This one is close, but uses named ranges
http://stackoverflow.com/questions/2...cent-cell-text