Just to join the chorus here, wildviper, it is possible, perhaps now more than ever. As merc1234 mentioned, you really should start following The Frequent Miler's blog. His speciality is researching how to "manufacture" spending, while getting most of your money back, or perhaps, incurring a small loss - that's more than made up for by the value of the miles you rack up.

Here's a very conservative example, using my favorite, Ultimate Rewards points:

Chase Ink Bold/Plus 50,000 UR points (business card)
Chase Sapphire Preferred 40,000 UR points
Min spend for both: about 20,000 UR points is a reasonable expectation
Buy/sell items thru UR portal: 6 times x 50,000 points each = 300,000 points
AmEx prepaid card 2000 per month for 6 months = 60,000 points

This is just a super-quick example of a single credit card churn of only two cards, meeting the minimum spending (and taking advantage of category bonuses), and creatively using a single American Express prepaid card for your run-of-the-mill monthly expenses (Google 'Vanilla Reload'), along with some buying and selling through the Ultimate Rewards portal to take advantage of merchant bonuses ($2500 at a time, six times, taking advantage of a 20x bonus via double-dipping). This comes up to 470,000 points/miles in about six months. And that's honestly the bottom end of what's possible.