My current Lian-Li holds 8 (5 in the bottom vertically mounted HDD rack and 3 in the FDD/HDD rack w/ outside access). The moddel is PC65 usb, and it is an average sized mid tower. It also has 4x 5.25 bays. I would venture to guess that the larger 7x series of Lian-Li cases would easily accomidate 10 HDDs since I know I could fit 7 in here right now and 2 more if i removed the FDD that I don't use and got an adapter for the 5.25 bay that's open.