I spent a year in QA and watched the best testers (dedicated, observant, smart, literate) get ignored while the slackers who turned up for Full Contract interviews in suits got the full time contracts instead. Great logic there. (For the record I don't consider myself one of the "good" testers and got the hell out of there as fast as I could).

To this day I keep in touch with people in the department, most are either still there or got moved up the ladder one notch... in QA. Very occasionally you'll hear about people who became designers from QA through a combination of much luck and huge determination (we're talking practically writing entire design docs themselves to prove they had what it took). From my experience and talking to other people who spent years in test, we're talking one in a hundred maybe. The senior testers will sometimes be lucky enough to move into web production or marketing but there are much better routes to those positions. I have personally met one person who made it into design from test. One.