I hope others chime in here because this problem has me intrigued!
Based on what I know, I think you are going to have a tough time with this one for two reasons: (1) you are saying it is a studio environment and (2) you want ghetto lighting, which I interpret as continuous, rather than flash, lighting.
So, taking the problem as given, you are going to need to put light on the background that is, if I calculate correctly, about 6 stops brighter (or more) than the light on the subject to get a black silhouette on a white background -- in what I interpret as a rather small studio. I really do not know how you would do this without a LOT of space between the background and the subject and virtually nothing that would reflect light back onto your subject.
Here's my best shot: You'll need two rooms separated by a doorway. Ideally the first room (which will be the room with the lights) will have a white wall. If not, you'll need something white, maybe something like a plastic shower curtain. Put all the light you can find on that shower curtain (but keep the types of lights consistent, such as all tungsten). Put the subject and the camera in the second room. Keep all the lights off in the second room. Have the subject stand a few feet inside the room framed by the doorway. Use as long as a lens as you can, and frame the subject within the doorway. Shoot, and hope for the best.
See, by putting the light in the other room and shooting in a dark room, you might be able to avoid light contamination. Even if it is not perfect, I would think that you would get enough differentiation between the background and the subject to use a Levels adjustment in PS to get black on white. Using one room for the lighting and the other for the shooting will make the walls of the lighting room act as flags to keep the light off of the subject.
If you can get access to a flash, it might be easier. The following picture I took in close quarters with ALL of the house lights on (for focusing). It is SOOC, except for some sharpening. And the wall behind my daughter is indeed white. But at f/14 and 1/200, none of the ambient light shows. This picture also shows perhaps a second method of getting what you want: If you can isolate the subject on a background that is not pure white, you can maybe get close enough to pick a color channel (the red channel in my picture) that you could easily convert to black on white.
Good luck! And if you succeed (or don't), PLEASE post your picture and tell us your method. I for one think I would learn something new! (Too many disappear after asking a question and leave us hanging.)
