I don't think that anyone would think that Apple would sell a quad core mini-tower for less than the price of a MiniMac - but Apple could make a nice mini-tower and sell it for its usual margins.
You should look at the Dell Precision Workstation 390 as an example of what Apple could do. A quad 390 is about $1000 less than a similarly configured entry Mac Pro.
It's a quality built, very quiet system. It has a lot of BTO options (SATA/SAS/15K RPM disk/graphics...).
You have your tech titans confused, Bill Gates is the one who is doing something to help the third world.
http://www.gatesfoundation.org
i agree that a mini tower would be nice from Apple.
Bill Gates might be giving away some of his money, but look at what he's done to his shareholders