AFAIK, all digital video cameras do exactly that: they digitize the sensor using 10 to 12 bits and map the values to 8 bits using a non-linear gamma transform. On the more expensive ones the user can adjust the gamma, Knee level and master pedestal according to his/her tastes. This is possible on the Canon H1, A1/G1 and I suppose also on the Sony V1. Typically, the user will adjust the Knee point lower to avoid oversaturating highlights (e.g. in concert show), press the blacks to hide the noise in the darker parts of the picture or, on the contrary, extend Knee point for a high-key effect, increase the blacks fr a low-key effect or lower the gamma if a softer picture is wanted.

Of course, each of those settings has an effect on the dynamic range as perceived after reduction to 8 bits for recording on the tape.