Comment 1 for bug 896248

This can already be done sorta. Create a paradrop SW which is invisble and autofires, heck you can include a sound with something like "Cargo on the way". Have the Sw target the building itself, drop self destroying"either suicide based units or some kind of suicide animation" Units which have cratesbeaneath set to true. Thus your building will call in a plane/s every x time and drop off x cash crates. You could even attach a secondary Paradrop SW which goes off every 3rd time the original paradrop SW goes off, thus making Money drops seem more random.

Of course money crates will have to be manually collected.