If you have a meter and a 200 amp breaker in an enclosure on a pole in the field 100' away from the house with a 2" conduit turning up at the house and lb'd into a MLO Panel in the house.
Can you legally put a Transfer switch on the Outside of the House just before it goes into the MDP or does it have to be next to the 200 amp breaker at the meter pole?
I believe you may be confusing service conductors with feeder conductors. This thread has been in reference to Article 230 services where the transfer switch was being installed as the first disconnect past the meter and you are referencing feeders Article 225. There would be no problem by installing the transfer switch on the outside of the house without an OCPD. In fact you may be correcting a violation of section 225.23 if the MLO panel inside the house has more than six breakers installed in the panel.
This transfer switch is required to comply with Article 225. See section 225.32 for the location of the transfer switch with relation to where the conductors enter the building and 225.36 requiring the transfer switch to be service rated.
Also, there is no problem with having the service equipment on a pole 100 feet from the house.