For those who are worried about the income level - don't worry about it. CIC won't deny a sponsor unless they are on welfare. If you're not on welfare, and have provided reasonable information about how you intend to support yourself and your family, you'll be fine. If CIC has doubts, they will ask for more information, not deny you right away. So you'll have a chance to explain.
For unemployed/housewife situation: it's also OK if it's the applicant that is likely to get a job faster because of previous work experience etc. If asked, then the sponsor can explain how the qualifications of the applicant are relevant to the work market in Canada, and how that will come into play.
Stage 1 is a fairly "easy" one : CIC will check if the sponsor is on welfare or not, criminal background, and check if they are eligible to sponsor the person (married, common law, conjugal). that's about it... the second stage is when CIC actually looks at the proofs etc, it takes much longer.
Good luck to all,
Sweden