No the vehicle has to fit their specs which are rather specific. Some specs are seemingly "low tec" in some areas but not in others. For example range:a lot of routes do not exceed 50 km but standard manufacturers cramp as much range as possible into their vehicles thus driving the weight and price up. A delivery vehicle like this does not need the range but good luck telling that your average car manufacturer who also has to think about other customers (who usually care a lot about range).

Then the vehicle has a hight floor making it back friendly for the delivery person which is something unwanted in your average delivery truck. It limits the height of the goods you can transport but the Post does not deliver packages that huge.

This is a special vehicle for a certain purpose and no commerial manufacturer had interest in developing something like this.