I was in both cities for a while last summer, and I never found a single tobacco shop (beyond cigarettes and cigars) in either city. I also never saw a pipe smoker in either city (or anywhere in SE Asia where I spent most of the summer), so I wouldn't plan of finding any. Singapore has some tough tobacco laws regarding bringing some in, but it seems they hardly ever check at immigration.
Never saw any locally carved pipes, other than old opium pipes at the Peranakan Museum. Singapore's a great (although expensive) city. Jakarta has the worst air quality and worst traffic of any city in the region (though Manila could give it a run for the money). If you have a video option on your camera, get some action shots of the motos zipping in and out of the crawling traffic jam you'll probably be in.
Natch