Even tho I have owned the iStar case I recommended for 3 years now, I completely forgot that it ALSO has 2 3.5" bays below the 5.25" bay stacks, for a total for 2 external 3.5" bays ... that means if you really wanted to go ham you can do 10 3.5" drives in trayless hotswap cages PLUS 4 external 2.5" SSD or spinning HDDs in 3.5" hotswap cages for your OS or ingesting entire HDDs easily.
Or use one 3.5" bay for twin hotswap SSD and the other 3.5" for an SD card reader ingesting station like this