If you are really keen, you can take the front wheel off your bike and put your bike in a bike bag (
http://www.flyingball.com have some bike bags for a few hundred HKD). This is generally acceptable on trains, and I am also told most double decker buses. I know this is very contrary to popular belief, but I have been advised the above by people who do this, and have seen people get on/off trains with their bikes in bags. I have also seen people on off peak trains getting off with the bike and no bag, just the front wheel removed.
Bikes are definitely allowed in elevators, unless you are unlucky enough to have some really unreasonable security staff. As far as bringing your bike goes... maybe you should see what is here before you ship your bike over. There are some cheap/well priced bikes here, good brands with decent specs.
