So I'm from Hong kong, and FD cases are not available here.

I was looking at the Arc Mini or Define Mini, and now I need some alternatives - any suggestions? Looks like the TJ08 is a popular choice here.

I need at least 5HD slots, and will fit a 660Ti in it...

There's also the Cooler Master Elite 341, which is a lot cheaper but the quality also feels very cheap. But it's should be good enough, and there's room for two 120 mm side fans. You could add a fan here to cool the GPU. There's also the old Antec P180 Mini.

Corsair 550D http://www.silentpcreview.com/Corsair_Obsidian_550D

But if your 5 HHDs are all 3.5", then the Temjin will be too small. Besides, fitting 5 3.5 HDDs without to much noise or vibrations is a challenge for any case.