Go dancing in custom leather for cheap.
Step 1: Acquire scrap leather
I found mine at the East Bay Depot for Creative Reuse in Berkeley in the form of an old belt (pink), an old skirt (green), and some furniture cover samples/scraps. Other good sites for scrap leather acquisition: Dollar-A-Pound in Cambridge, MA; yard sales; Goodwill; your grandmother's attic; butcher shops for the real DIYer.
Fake fur makes an especially tasteful accent; be creative.
Step 2: Make a bikini: pattern
The most careful work must go into creating a bikini-style base for your top, as it's the most difficult to fit. If the Instructable for bra making had been up at this point, I'd have followed it; as it was, I made a bad pattern from one of mine.
Trace the pattern onto the leather, making sure you mark the orientation properly. Add fake fur to the top, as this will (partially) help cover up the fact you've used a crappy pattern.
Step 3: Measure twice, cut and sew
Get a friend to help you with this one. Hold the two cups of the bikini top where you actually want them to sit, then measure what size connector you'll need.
Trace and cut out a pattern, double-check it, then actually cut your leather and sew the thing together.
Check again, just to make sure, as this is the most squirrelly piece to fit.