I've found the HK ISP's very reliable. Outages do occur every now and then (we've had a few on our main ISP and had to revert to the backup a handful of times) but that is the norm anywhere. Even a lease line can get cut off - just think about all the construction in HK and I'm surprised it doesn't happen more often.
I'd try the broadband route first or a dedicated 64-256K line to your ISP. However, if you really want to explore a direct connection into our office, you should contact our salesperson (send me a PM if interested and i'll give you his details). The cost of the line is not the only cost though. For a lease line, you will charged a monthly minimum in commission. If you are trading high volume, then it might be cost effective.
BTW, our trade desk in HK is quite responsive. If our service goes down, just give us a call or start a chat and we should be able to get you out of your trade.