I've also tried to find decent vinyl stockists in HK.
If you like 60's/70's music - there is a decent place on Chatham Road, TST, called 'Used Records Market' - you can pick up loads of albums from that era for around HK$50/album, which is a bargain.
The other places I've found tend to be ridiculously overpriced (including HMV - HK$80/12").
I have never checked out Rendezvous Records though, so might have to check it out.
I've found that ordering from the internet is probably the best thing, especially if it is for hard to find dance/hip-hop/reggae/dancehall etc. but I do miss my days of perusing through record shops in London.
Check out
www.yp.com.hk & search for cd retailers - it brings up a list of all music retailers - I'm going through that list, hoping to find a gem & will keep you informed of any progress....