Natural Adder,
If a corporation is consistently running out of supplies, create a corporation that produces those supplies and then contract your production to the corps that are running out.
I experienced exactly the same problem with Solid Missile Fuel. So I built my own Solid Missile Fuel Corp, and sell it's production, to my Corps that were running out of supplies.
It's a useful way to find out what kind of products are in extreme shortage. Since if Corps can't buy enough to keep producing, chances are, the product they are running out of, will be very profitable.
Signed President of DanNation on LU