Or just do it all real low key and don't let anybody in officialdom know anything. I know of several companies here, such as private schools and media groups that hire people from overseas; they come in on tourist visas, go to Singapore to renew it a couple times for the first 3 months or so and no taxes are paid at all -- that is before they are given a formal contract and required to pay taxes and get the kitas type visa.
Yes it's technically not legal, but people do it all the time and for some reason, companies that hire Westerners ("bule") seem to get away with it easier than, say, if they were hiring a person from Taiwan or Nigeria.
Kuku should have more options for you to ponder as well....
Just here proffering my pearls to swine, my throat to wolves and my trousers to the flagpole.