Bump with added ideas:
Kidnapped Test Subject
Similar to the above, but as a non-consensual (or non-con to con) setup. You are abducted by a mad scientist who needs test subjects for his exotic formulae.
Another concept/plot/idea/thingy:
Belt Station 47
When humans begin colonizing space, some few develop MHS- Microgravity Hypertrophy Syndrome. A person's body will suddenly react badly to the lack of gravity, and certain areas will begin sudden, accelerated growth. Typically, this will be the 'fatty areas': breasts, belly, ass, or thighs. The Syndrome is easily cured.... except in this case, the nearest dose of medication is days/weeks away.