I don't have a complete list, but there are several DO post-baccs out there. Besides the mentioned UNT-Biomed, I know PCOM, LECOM, & KCUMB have similiar programs. (Since there are only 20 DO schools it would not that be hard to check out the programs offered at all you may be interested in.)
At PCOM the first year is intense course work at the grad/med level. A certificate is awarded.
The offerings focus on what you will actually will be learning in the first year. Since you will be learning anatomy (with cadavear), histology, biochem etc. it can really prepare you for success at med school. One normally has the option to stay the second year to complete the masters.
If possible it is best to have done reasonably well on the MCAT before entering. They will still be important & a lot to balance in April of the first year.