27.2 is one of if not the most common size post used in high quality steel MTB frames. My Reparto Corse Martini Racing Bianchi, Bridgestone MB1s, Waterford 1400/2400, etc all run 27.2 posts. I also have a Indy Fab deluxe that has some damage done to it and IF bonded a custom fiberglass shim in the frame to take it from a 29.4 to a 27.2 and told me to never worry about it because it will last forever.
Soulcraft even provides a shim on their Option 3 to take it from a 28.6 down to a 27.2 to offer additional post selections.
You will likely find the ride more compliant too as the post will have a bit more natural flex.