Have you tried contacting Toni from a herp?
He could really tell you where things are more than Angus. Angus doesn't get out as often as Toni (Hong Kong wise...)
The main street that has the herps for sale in HK are on 'fish street' where you've already been. I remember that there are around 4 or 5 shops with herps there.
"Birdie Street" is also a nice place to visit if you want to go and take a look at things, its located in Prince Edward Station
Other than that....there isn't much reptile stores around anymore...(heck there aren't much animal shops around either...)
If you want to try the snake soup, go to Wan Chai Market and there should be a couple there. Most of the snakes they use there are blue beauties, taiwan beauties and other beauties (they're large enough with meat and everything.....
Have fun in HK!!
I love it there...heck I was from there!! LOL!!