You looking for a proper hotel or a love hotel?
Theres "Mingle at the Eden Hotel" on 148 Wellington Street on the way to Sheung Wan, part of the Mingle Hotel group.
http://www.mingleplace.com/
When I went there last with a ktv girl I met outside work, the room I got was 300 for 2hrs, rooms are small (enough to fuck) but there are better rooms.
Not sure about full on hotels though.