There are TWO (2) full duplexes for sale - listed in correctly in MLS and stumbled across them.
One is is Central Ft Worth, solid location for under $400k. Larger units, Market rent is $1500 per unit.
The second is in Mansfield ISD, newer build, part of larger single family community. $465K with rents of $1950 and $1770. Both in desired locations especially for owner occupy.
Email for details.