Costa Bello ( Villa's ) in Sai Kung will be exactly what you want, the ground floor of those is 1200 ft2, 3 bedrooms and a maids room, including a private court yard that faces right onto the bay, including a decked patio. They also have a sunken lounge and are pretty new. you can literally fish off your deck. Its also a 5 minute walk from the shops and the bus terminus.
Rents are around the 38,000 per month mark.
1500ft2 might be a bit difficult though as its an odd size, they are usually in 700ft floors, and you'll soon see when you get here that no two buildings will share the same internal floor space even when they state the same floor area. Lots of unregulated property dealing here lol.
Take look around first and see what size suits you best when you get here. Having a back yard is also uncommon in Hong kong, but you'll have open space that surrounds your home in most cases in Sai Kung.
Another villa complex worth looking at is Jade villa's.
If you dont mind going a bit further out, there are some brand new 2100ft2 tri level inc balconey and roof top terrace village houses about 3km along Yan Yee road, tai Mong Tsai, on your right hand side owned by Mr Wang ( Wong ), the agents in the Sai Kung area will all know which ones they are. They are about as nice as I have seen on an interior design point of view. The wangs spend a lot of time in Australia, and it definitely shows in how they did the downstairs family room and open plan kitchen. Timber venetian blinds were used throughout the entire home, including the first intance that I have seen timber window surrounds, in Hong Kong. Job well done. .
They'll set you back about mid 40's though.