Hi,
Most one year programs require significant public health or medical experience prior to admission. You might consider doing medical school first, and then doing your MPH. This is probably the best route, since you'll then have a medical context upon which to orient your MPH training. One can also do a one-year MPH between the 3rd and 4th years of medical school. We have around 40 medical students from various schools in the Hopkins MPH class this year. You can find out from the SDN discussion archives lots of information about which schools offer 1 year programs, deadlines, etc.
Best of luck!