I just bought the Rock Band Special Edition - PS3 last Saturday in Mong Kok. Here's the place:
Ho King Commercial Centre
2-16 Fa Yuen Street
Mong Kok
You guys can look for specific directions in Centamap, it's quite easy to find. It's even easier if you go down the Yau Ma Tei MTR station and take the nearest exit to Fa Yuen Street (I think it was A2).
When you get to the commercial centre, simply go to the second floor via escalator, and the first store you see WILL have it!
Purchase includes: game + microphone, guitar and drum set peripherals
Wish all of you who have been looking for this great luck! I've been searching for this game for almost a year now (been knocking my head for being unwilling to buy it from the US my last visit) and now I'm glad I've found it.
Give me a buzz if you're looking for an online band member too.
Rock On!
p.s. PS3 set cost HKD1,720.00