Thank you for the heads up and you gave me a great idea Gilsalot. People always underestimate Apple. The MacMini cannot expand internally however it does have 2 Thunderbolt 2 ports, Thunderbolt carries the PCIe protocol. I can buy a Thunderbolt 2 to PCIE hub and connect as many USB controllers as I want that way. might be pricy for the hub but better then building another computer, which I might do anyway. Ill keep everyone posted.
Ive also tried adding some of the Seagate 8TB drives that have the 2 USB ports on them to see if I can get more that way but I wont know till I plot a few more drives.