There is no example of this sort in Rome, but in Athens there is the octastyle in the precinct of the Olympian.
The hexastyle temple is necessarily more high and more narrow than the octastyle building.
octastyle: Having eight columns, when said of a portico; having eight columns in front, when said of a temple or similar building.
It was peripteral, octastyle; that is, surrounded with a portico of columns, with eight to each façade.
If an octastyle is to be constructed, let the front be divided into twenty-four parts and a half.
Hexastyle: Having six columns; as in the case of octastyle for eight.